Hello.
I'm having a weird issue on mobile with this module.
New install ZC1.5.7d and OPC 2.3.11
In trying to checkout as a guest, after entering the contact/billing/shipping info and pressing the SAVE CHANGES button I'm getting a blank page and the following error
in the logs

#1 trigger_error() called at [/includes/classes/OnePageCheckout.php:1310]
#2 OnePageCheckout->validateAndSaveAjaxCustomerInfo() called at [/includes/classes/ajax/zcAjaxOnePageCheckout.php:401]
#3 zcAjaxOnePageCheckout->validateCustomerInfo() called at [/ajax.php:85]
--> PHP Fatal error: validateAndSaveAjaxCustomerInfo, invalid POST: array (
'email_address_conf' => '[email protected]',
'telephone' => '',
) in /includes/classes/OnePageCheckout.php on line 1310.

It's only happening on mobile, but not on desktop.

Any idea what could be causing this?

Thank you!