One-Page Checkout [Support Thread]

We are running zc 2.2.2 on php 8.2 and opc 2.6.2 now with some modsecurity rules disabled. most folks having no problem now, but we just had another that for some reason got a 500 server error during checkout. placed an order twice and still had the items in his cart. Is this possibly a common issue? Would it be resolved by upgrading to the 2.6.3 version. Also this is all with authorize aim.

If I'm to upgrade, should I just overwrite existing files, or is there db stuff as well? Should I use the plugin manager to uninstall and re-install?

Thank you,
John

dbltoe:

FYI,

Files come down as 4.6.3 vs 2.6.3
Thanks for that; the upload's been corrected.

bumba000:

We are running zc 2.2.2 on php 8.2 and opc 2.6.2 now with some modsecurity rules disabled. most folks having no problem now, but we just had another that for some reason got a 500 server error during checkout. placed an order twice and still had the items in his cart. Is this possibly a common issue? Would it be resolved by upgrading to the 2.6.3 version. Also this is all with authorize aim.

If I'm to upgrade, should I just overwrite existing files, or is there db stuff as well? Should I use the plugin manager to uninstall and re-install?

Thank you,
John
OPC is not yet an "encapsulated" plugin, so the "Plugin Manager" doesn't participate in its installation/removal. You'll need to use the just published v2.3.6, which corrects a couple of issues.

OPC's readme.html identifies how to install/upgrade.

zc210. opc2.6.3

I just received the following warning. It is my first time to see this warning.

[29-Jul-2026 13:49:45 America/New_York] Request URI: /index.php?main_page=checkout_one, IP address: xxxx, Language id 1
#0 /includes/templates/template_default/templates/tpl_modules_opc_address_block.php(157): zen_debug_error_handler()
#1 /includes/templates/template_default/templates/tpl_modules_opc_billing_address.php(14): require('/')
#2 /includes/templates/template_default/templates/tpl_checkout_one_default.php(60): require('/')
#3 /includes/templates/responsive_classic/common/tpl_main_page.php(187): require('/')
#4 /index.php(94): require('/')
--> PHP Warning: Undefined array key "telephone" in /includes/templates/template_default/templates/tpl_modules_opc_address_block.php on line 157.

Line 157 is the following.

njcyx:

zc210. opc2.6.3

I just received the following warning. It is my first time to see this warning.

[29-Jul-2026 13:49:45 America/New_York] Request URI: /index.php?main_page=checkout_one, IP address: xxxx, Language id 1
#0 /includes/templates/template_default/templates/tpl_modules_opc_address_block.php(157): zen_debug_error_handler()
#1 /includes/templates/template_default/templates/tpl_modules_opc_billing_address.php(14): require('/')
#2 /includes/templates/template_default/templates/tpl_checkout_one_default.php(60): require('/')
#3 /includes/templates/responsive_classic/common/tpl_main_page.php(187): require('/')
#4 /index.php(94): require('/')
--> PHP Warning: Undefined array key "telephone" in /includes/templates/template_default/templates/tpl_modules_opc_address_block.php on line 157.

Line 157 is the following.

<?= zen_draw_input_field('telephone[bill]', $address['telephone'], $telephone_field_length . ' id="telephone" class="phone" placeholder="' . ENTRY_TELEPHONE_NUMBER_TEXT . '"' . $telephone_required, 'tel') ?>

I'm seeing how to "patch" this, but I'm having a hard time determining where the 'telephone' element of the billing address disappeared to.

Our multiple checkouts without clearing the cart contents have been resolved. https://www.zen-cart.com/showthread.php/231165-Frequent-Duplicate-Orders-Cart-Not-Emptying?p=1412054#post1412054

zc210. opc2.6.3

I just received the following warnings. It is my first time to see this warning.

1st.

[06-Aug-2026 18:36:10 America/New_York] PHP Notice: unknown 'bill' address_book_id (15xxxx) for customer_id (109528) in /includes/classes/OnePageCheckout.php on line 1241

109528 is the OPC generated customer in my site. Line 1241 is the following.

trigger_error("unknown '$which' address_book_id ($address_book_id) for customer_id (" . $_SESSION['customer_id'] . ')', E_USER_NOTICE);

2nd. Same time as 1st.

[06-Aug-2026 18:36:10 America/New_York] Request URI: /index.php?main_page=checkout_one, IP address: xxxx, Language id 1
#0 /includes/classes/OnePageCheckout.php(1250): zen_debug_error_handler()
#1 /includes/classes/OnePageCheckout.php(1214): OnePageCheckout->getAddressValuesFromDb()
#2 /includes/templates/template_default/templates/tpl_modules_opc_address_block.php(24): OnePageCheckout->getAddressValues()
#3 /includes/templates/template_default/templates/tpl_modules_opc_billing_address.php(14): require('/...')
#4 /includes/templates/template_default/templates/tpl_checkout_one_default.php(60): require('/...')
#5 /includes/templates/responsive_classic/common/tpl_main_page.php(187): require('/...')
#6 /index.php(94): require('/...')
--> PHP Warning: Attempt to read property "fields" on array in /includes/classes/OnePageCheckout.php on line 1250.

[06-Aug-2026 18:36:10 America/New_York] Request URI: /index.php?main_page=checkout_one, IP address: xxxx, Language id 1
#0 /includes/classes/OnePageCheckout.php(1250): zen_debug_error_handler()
#1 /includes/classes/OnePageCheckout.php(1214): OnePageCheckout->getAddressValuesFromDb()
#2 /includes/templates/template_default/templates/tpl_modules_opc_address_block.php(24): OnePageCheckout->getAddressValues()
#3 /includes/templates/template_default/templates/tpl_modules_opc_billing_address.php(14): require('/...')
#4 /includes/templates/template_default/templates/tpl_checkout_one_default.php(60): require('/...')
#5 /includes/templates/responsive_classic/common/tpl_main_page.php(187): require('/...')
#6 /index.php(94): require('/...')
--> PHP Warning: foreach() argument must be of type array|object, null given in /includes/classes/OnePageCheckout.php on line 1250.

[06-Aug-2026 18:36:10 America/New_York] PHP Fatal error: Uncaught Error: Attempt to modify property "fields" on array in /includes/classes/OnePageCheckout.php:1268
Stack trace:
#0 /includes/classes/OnePageCheckout.php(1214): OnePageCheckout->getAddressValuesFromDb(154952, 'bill')
#1 /includes/templates/template_default/templates/tpl_modules_opc_address_block.php(24): OnePageCheckout->getAddressValues('bill')
#2 /includes/templates/template_default/templates/tpl_modules_opc_billing_address.php(14): require('/...')
#3 /includes/templates/template_default/templates/tpl_checkout_one_default.php(60): require('/...')
#4 /includes/templates/responsive_classic/common/tpl_main_page.php(187): require('/...')
#5 /index.php(94): require('/...')
#6 {main}
thrown in /includes/classes/OnePageCheckout.php on line 1268

[06-Aug-2026 18:36:10 America/New_York] Request URI: /index.php?main_page=checkout_one, IP address: xxxx
--> PHP Fatal error: Uncaught Error: Attempt to modify property "fields" on array in /includes/classes/OnePageCheckout.php:1268
Stack trace:
#0 /includes/classes/OnePageCheckout.php(1214): OnePageCheckout->getAddressValuesFromDb(154952, 'bill')
#1 /includes/templates/template_default/templates/tpl_modules_opc_address_block.php(24): OnePageCheckout->getAddressValues('bill')
#2 /includes/templates/template_default/templates/tpl_modules_opc_billing_address.php(14): require('/...')
#3 /includes/templates/template_default/templates/tpl_checkout_one_default.php(60): require('/...')
#4 /includes/templates/responsive_classic/common/tpl_main_page.php(187): require('/...')
#5 /index.php(94): require('/...')
#6 {main}
thrown in /includes/classes/OnePageCheckout.php on line 1268.

[06-Aug-2026 18:36:10 America/New_York] Request URI: /index.php?main_page=checkout_one, IP address: xxxx
--> PHP Fatal error: Uncaught Error: Attempt to modify property "fields" on array in /includes/classes/OnePageCheckout.php:1268
Stack trace:
#0 /includes/classes/OnePageCheckout.php(1214): OnePageCheckout->getAddressValuesFromDb(154952, 'bill')
#1 /includes/templates/template_default/templates/tpl_modules_opc_address_block.php(24): OnePageCheckout->getAddressValues('bill')
#2 /includes/templates/template_default/templates/tpl_modules_opc_billing_address.php(14): require('/...')
#3 /includes/templates/template_default/templates/tpl_checkout_one_default.php(60): require('/...')
#4 /includes/templates/responsive_classic/common/tpl_main_page.php(187): require('/...')
#5 /index.php(94): require('/...')
#6 {main}
thrown in /includes/classes/OnePageCheckout.php on line 1268.

Line 1250 is the following

foreach ($address_info->fields as $key => $value) {

Line 1268 is the following.

$address_info->fields['telephone'] = $telephone->fields['customers_telephone'] ?? '';

Not sure if it is related to the warning I found by the end of last month.

That's yet-another issue, that indicates that somehow (?) the guest-customer's bill-to address book id is corrupt. Are both the bill-to and ship-to address book records present for that guest customer id?

Hi @lat9,

I didn't turn on the log for opc, unfortunately.

The customer_id in the log looks good, which is the one created by OPC. I don't know how to check the bill-to and ship-to address book records...

Also, it is an intermittent issue and it didn't happen in the last weekend.

njcyx:

Hi @lat9,

I didn't turn on the log for opc, unfortunately.

The customer_id in the log looks good, which is the one created by OPC. I don't know how to check the bill-to and ship-to address book records...

Also, it is an intermittent issue and it didn't happen in the last weekend.
Check the address_book table. You should have two entries with an entry_lastname of Customer, do not remove ... one for the default guest billing address and another for the guest shipping address.

I checked web portal (customers--customers) and I found customer_id (109528) with two entries as the following.

Customers
Address Book Entries
NOTE: A maximum of 10 address book entries allowed.

Guest Customer, do not remove (primary address)
Guest Customer, do not remove
Default billing address
State
United States

Guest Customer, do not remove
Guest Customer, do not remove
Default shipping address
State
United States

I also checked my database, address_book and I can find two records under the same customers_id (109528). One for billing and one for shipping. Both have the different address_book_id.

njcyx:

I checked web portal (customers--customers) and I found customer_id (109528) with two entries as the following.

Customers
Address Book Entries
NOTE: A maximum of 10 address book entries allowed.

Guest Customer, do not remove (primary address)
Guest Customer, do not remove
Default billing address
State
United States

Guest Customer, do not remove
Guest Customer, do not remove
Default shipping address
State
United States

I also checked my database, address_book and I can find two records under the same customers_id (109528). One for billing and one for shipping. Both have the different address_book_id.
OK, that's to be expected. The 'missing' address book id issue that you'd posted above; I've seen where that can arise in the code and am working to correct that.

Sometimes I noticed that my database is offline, for a very short period of time. Not sure if it is due to the server issue, or due to the DDoS attack. When the database is offline or partially offline, strange warning file(s) would be generated. It may be from OPC or from some other plug-ins. That might be the reason why sometimes I will notice some intermittent warning, I guess. But most of time, everything works fine with no warning files.

I have installed checkout one , everything working except guest checkout , the error it gives in log file as at follows

2026-08-31 09:57:05 checkout_one: CHECKOUT_ONE_AFTER_PAYMENT_MODULES_SELECTION
{}
(not set)

what to fix

diptimoy:

I have installed checkout one , everything working except guest checkout , the error it gives in log file as at follows

2026-08-31 09:57:05 checkout_one: CHECKOUT_ONE_AFTER_PAYMENT_MODULES_SELECTION
{}
(not set)

what to fix

That's not a log, that's part of an OPC debug trace (since OPC's Enable One-Page Checkout Debug setting is set to true). If there is a log it will be in a file named myDEBUG*.log.

You've also not indicated the version of Zen Cart or OPC that you're running; please provide that information for future assistance.

lat9:

diptimoy:

I have installed checkout one , everything working except guest checkout , the error it gives in log file as at follows

2026-08-31 09:57:05 checkout_one: CHECKOUT_ONE_AFTER_PAYMENT_MODULES_SELECTION
{}
(not set)

what to fix

That's not a log, that's part of an OPC debug trace (since OPC's Enable One-Page Checkout Debug setting is set to true). If there is a log it will be in a file named myDEBUG*.log.

You've also not indicated the version of Zen Cart or OPC that you're running; please provide that information for future assistance.

zencart version v2.2.2, opc version 2.6.3 (2026-07-21) , no log filegeneration as value not psting , page is standstil nothing happens,try a guest checkout and see the issue https://keys4urride.com/index.php?main_page=checkout_one

I was going to see what happened, so I went to checkout as a Guest on your site.

As soon as I filled in the initial information (email and billing), I see the following error under the Inspect Tools:

Error Code 418 - https://keys4urride.com/ajax.php?act=ajaxOnePageCheckout&method=validateCustomerInfo

https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/418?utm_source=devtools&utm_medium=devtools-netmonitor&utm_campaign=default

Apparently that code is the same as a 503 error on your server's end.

So I can't even get past your Contact Information page.

jeff_mash:

I was going to see what happened, so I went to checkout as a Guest on your site.

As soon as I filled in the initial information (email and billing), I see the following error under the Inspect Tools:

Error Code 418 - https://keys4urride.com/ajax.php?act=ajaxOnePageCheckout&method=validateCustomerInfo

https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status/418?utm_source=devtools&utm_medium=devtools-netmonitor&utm_campaign=default

Apparently that code is the same as a 503 error on your server's end.

So I can't even get past your Contact Information page.

Thanks , so what its for me to fix , or its a totaaly server issues ?

v2.7.0 of One Page Checkout is now available for download: https://www.zen-cart.com/plugins/one-page-checkout-one-page-checkout-vb2095

This release contains changes associated with these GitHub issues:

#475: Correct PHP Deprecated issue on upgrade.
#477: Adding zc300's ALLOWED_METHODS constant to the AJAX handler.
#476: Correct telephone-update for logged-in customers.
#479: Disallow a shipping module-id of 'title'.
#481: setAddressFromSavedSelections should apply only to logged-in customers.
#483: resetGuestSessionValues should apply only when guest checkout is in progress.
#485: Dropping support for Zen Cart versions prior to 2.0.0; minimum PHP requirement is now 8.0.
#486: Ensure 'enforcement' of maximum number of address-book entries per customer.
#488: Additional validation that a payment method is allowed for guest-checkout.
#490: 'Tighten' pre-requesite checks for various AJAX methods.
#493: Use const for javascript constants; was using var.
#492: Remove use of console.log and reduce PHP-based debug trace.
#495: Move detection of missing AJAX jQuery to storefront script.
#501: Move country selection prior to state in address-gathering forms.
#502: Add missing 'EMAIL_GREETING' from guest account-creation emails (zc158 and zc210).

Hi @lat9, thanks for your updates.

I noticed that, the address form in the checkout page was changed in this update. In the past, the format is

Address line 1, address line 2, city, state, zipcode, country.

Now the format is

Address line 1, address line 2, city, country, state, zipcode.

Honestly speaking, the new format looks very strange to me and I still prefer the previous format. I'm not sure if you can start a poll in this forum and let the users vote. But I will vote the previous format. I asked chatgpt for both formats and chatgpt agreed with me...