Whoops! Sorry, but you are not allowed to perform the action requested

After checkout completion, the order is confirmed, and payment is made too, and reached a time-out page with this error message:

WHOOPS! SORRY, BUT YOU ARE NOT ALLOWED TO PERFORM THE ACTION REQUESTED.

Tried paypal checkout (with payment) and other payment methods. Anyone knows why? The orders have successfully gone through, but instead of the order confirmation page, it reaches an error page.

Scroll down this page to see some of the similar posts. One of them may have the answer.
Always a good idea to search the forum for the error. Also, searching Google (with an added Zen Cart) can be helpful.:yes:

When you trigger that time-out page, is it a result of having gone through testing the payment process several times?

There's a safety feature built-in (since v1.3.9) which stops credit-card thieves from using your site to test whether their stolen cardnumbers are valid: If they go through payment more than 3 times without successfully getting approval, it logs them out and sends them to the timeout page.

It could also be something broken on your server which is causing the customer to be logged out (or their session lost) before the last page. This is rare, but I suppose it could happen if you're using a "shared SSL" certificate (where the https domain is different than your http domain) and you're using 3rd-party payment modules that don't know how to keep sessions across complicated SSL setups.

Not enough information here to offer further insights.

DrByte:

When you trigger that time-out page, is it a result of having gone through testing the payment process several times?

There's a safety feature built-in (since v1.3.9) which stops credit-card thieves from using your site to test whether their stolen cardnumbers are valid: If they go through payment more than 3 times without successfully getting approval, it logs them out and sends them to the timeout page.

It could also be something broken on your server which is causing the customer to be logged out (or their session lost) before the last page. This is rare, but I suppose it could happen if you're using a "shared SSL" certificate (where the https domain is different than your http domain) and you're using 3rd-party payment modules that don't know how to keep sessions across complicated SSL setups.

Not enough information here to offer further insights.

The time-out page is triggered after the checkout process is completed, regardless of payment method. I tried with paypal payment, and payment by reward points, and cash payment etc, instead of reaching the order confirmation page, the time-out page is presented.

My cart was upgraded to 1.53 and it worked fine, until my upgrade to 1.54. I am not using SSL.

saplanet:

My cart was upgraded to 1.53 and it worked fine, until my upgrade to 1.54.
Since it doesn't do the "whoops" problem on a fresh brand new uncustomized install of Zen Cart, my next question is: what are ALL the ways in which your site is different from a fresh brand new unaltered Zen Cart install? Therein probably lies the solution.

saplanet:

After checkout completion, the order is confirmed, and payment is made too, and reached a time-out page with this error message:

WHOOPS! SORRY, BUT YOU ARE NOT ALLOWED TO PERFORM THE ACTION REQUESTED.

Tried paypal checkout (with payment) and other payment methods. Anyone knows why? The orders have successfully gone through, but instead of the order confirmation page, it reaches an error page.

Check this PHP configuration setting:

1. Admin->Tools->Server Info ... Press CTRL+F to "search the page" and search for session.hash_bits_per_character
2. If session.hash_bits_per_character is set to 6, then you'll need to apply this fix: http://www.zen-cart.com/showthread.php?215694&p=1270902#post1270902