A partially rendered page in reply to the "add to cart & checkout" button

[v_melnik]

Hello,

 

When user clicks to the "add to card & checkout" button, they get the following reply:

 

 

Everything worked perfectly a couple of days ago, but today it has stopped working. Tried upgrading to v6.1.1, but with the same luck. Displaying errors option doesn't help too: there are no error messages neither on the page nor in the apache's error.log.

 

Would anyone be so kind as to share any ideas on where should I look up?

 

Thanks!

[sentq]

The first thing to do is to check your WHMCS Activity Log from admin area, then enable the Display Errors option and try to replicate the issue again and if there is any PHP errors WHMCS will print it to your screen.

[v_melnik]

The support team suggested to change the Default template to the Six one, it helps! Thanks to all!