Registration fails, Admin Area Ticket Download fails too

Using the current version 5.10.0 on Joomla 5.4.7 an error occurs during registration:

When people try to register for an event and enter their billing information, accept the terms & conditions and check the privacy checkbox too, the system will fail after hitting the "next/send" button at the end.
A broken page will show up and tell:

array_push(): Argument #1 ($array) must be of type array, null given
(see attached Screenshot named "eb-register-2026-10-09")
The users don't get any email with tickets, but they will show up in the registrants list in the backend.
If you try to use the "download ticket" button as an administrator in the backend, the same error will show up.

array_push(): Argument #1 ($array) must be of type array, null given
(see attached Screenshot named "eb-backend-2026-10-09")

What can be done to fix this error?

In the admin backend, I already tried "tools/repair database scheme" and "tools/clear URLs", but the errors are still there.Please help, thanks very much in advance.
 

Hi Janet

For this, we will need to check it directly on your site. Please submit a support ticket sending us super user account of your site and tell us what we need to do to see the error

We are going to check to see why the issue happens and get it sorted

Regards,

Tuan

Thanks, Tuan, will do next week, because I'm nearly out of office for now and we all deserve a weekend
Best regards!

OK Janet. Have a nice weekend and we will solve it next week when you are ready

Regards,

Tuan