Checkout loop?

[BDog21]

the log folder has files, something about what it sent to authorize.net...i do have an authorize.net account that is still working fine...this is what the log file says (with all of the personal info replaced by XXXX)

Aug-28-2013 03:03:00
=================================

Sent to Authorizenet: Array
(
[x_login] => *******
[x_amount] => 25.00
[x_version] => 3.1
[x_method] => CC
[x_type] => AUTH_CAPTURE
[x_cust_ID] => 1
[x_email_customer] => FALSE
[x_company] =>
[x_first_name] => XXXXXX
[x_last_name] = XXXXXXX
[x_city] => XXXXXXX
[x_state] => XXXXXXX
[x_zip] => XXXXXXXX
[x_country] => United States
[x_phone] => XXXXXXXXX
[x_fax] =>
[x_email] => XXXXXXXXXX
[x_ship_to_company] =>
[x_ship_to_first_name] =>XXXXXX
[x_ship_to_last_name] => XXXXXXX
[x_ship_to_address] => XXXXX
[x_ship_to_city] => XXXXXXX
[x_ship_to_state] => XXXXXXX
[x_ship_to_zip] => XXXXXXX
[x_ship_to_country] => United States
[x_Customer_IP] => XXXXXXXXX
[x_relay_response] => TRUE
[x_relay_URL] => http://zone1supplies.net/shop/index....action=confirm
[x_invoice_num] =>
[x_duplicate_window] => 120
[x_allow_partial_Auth] => FALSE
[x_description] => Website Purchase from Zone One Supplies
[x_fp_sequence] => 290
[x_fp_timestamp] => 1377684180
[x_fp_hash] => XXXXXXXXXXXXXXXXXXXXX
[x_card_num] => XXXXXXXXXXXXXXXXXXXXXXX
[x_exp_date] => XXXXXXX
[x_card_code] => *******
[zenid] => XXXXXXXXX
[url] => https://secure.authorize.net/gateway/transact.dll
)

[BDog21]

nobody?

[lhungil]

A quick search of the forums found threads noting in order to test (or use) Authorize.NET one must have Zen Cart (and your website) both configured for SSL.

From looking at your website (briefly) It appears your SSL certificate is installed... But Zen Cart has not been configured for SSL yet.

A quick search using "Google" for "SSL site:zen-cart.com" found this article which has instructions for configuring Zen Cart for SSL.

I'd start by configuring your Zen Cart for SSL (and see if the problem goes away). If problems persist please read the "posting tips" and reply with answers to all the questions and with any other relevant information which may aid people in their attempts to help :)

[BDog21]

i enabled SSL on both my admin and my non-admin pages, and im still getting the same problem.

im using 1.5.1, havent upgraded at all i JUST installed it. as of yet i have no plugins or add ons besides a template but i get the problem even when i change back to the default template. php is version 5.3 and im not sure of the mySQL version but pretty sure its current.

[DrByte]

and i dont know if its relevant or not, but when it takes me to the login page there is no template on it, its just a plain white page with black text and thats it

Yes, it's relevant.
The blank-page is a symptom of encountering errors in PHP.
If the error isn't found in the /logs/ folder in myDebug-xxxxxxxxx.log files, then it should be in the server's Apache errorlog or the server's general PHP error log, both of which are accessible by your hosting company tech staff.
If the blank page is triggered by a mod_security issue on the server, then it's probably triggering a generic "500 internal server error" condition, which again only shows the details of the error in the server's logs, since it would be inappropriate to disclose security error details to the screen in case it was actually caused by a malicious visitor trying to do damage/fraud with your site. So ... back to the server's logs to find out the root cause.

i have it set up with my authorize.net account

Using which Authnet module? Is it AIM or SIM? What are the settings you've got set in the enabled module? (obviously don't post passwords or keys here)

im pretty sure it was working before

"before" what?

the log folder has files, something about what it sent to authorize.net...i do have an authorize.net account that is still working fine...this is what the log file says (with all of the personal info replaced by XXXX)

Aug-28-2013 03:03:00
=================================

Sent to Authorizenet: ...

Does the log file not contain anything about the response Received From Authorize.net? If not, then it usually means a PHP error occurred which is preventing it from processing the response ... which exactly corresponds with the blank-page symptom you mentioned.