BA Forms 2.4.3.1 – frontend submission returns 403

Hello,

after updating to BA Forms 2.4.3.1, forms could no longer be saved in the backend or submitted in the frontend – both returned HTTP 403.

Environment:
BA Forms 2.4.3.1
Joomla 5.4.7
PHP 8.5
IONOS shared hosting (Apache)

Current status:
I applied the file replacement your support suggested in this topic, which fixed saving in the backend:

https://www.balbooa.com/help/forums/forms/ba-forms-2-4-3-1---forms-cannot-be-created-duplicated-saved-or-imported#commentID-13627

Frontend submission still fails. When a visitor fills in the contact form and clicks submit, the POST request to /index.php?option=com_baforms returns HTTP 403 – nothing is stored and no notification email is sent.

One detail that may help: the 403 response carries server: nginx, while all regular requests return server: Apache. The request therefore seems to be rejected upstream before reaching Joomla, which would also explain why nothing appears in the Joomla or Apache logs.

This affects a live customer website where the contact form is the main way patients request appointments, so any guidance would be much appreciated.

Best regards