Today out of nowhere, The forum started showing message:

We logged into ACP and found a message stating, 2.3.6 Patch 2 available. One of the admin went ahead and installed it. It showed successful on completion but the Site still showed the same message. Hit up the server support to see if any issues on server side and after trying multiple things over past 3-4 hours nothing worked and now site shows this:
What could have caused this error and how to fix this? Server support is out of suggestion other than to restore a backup from previous day.

We logged into ACP and found a message stating, 2.3.6 Patch 2 available. One of the admin went ahead and installed it. It showed successful on completion but the Site still showed the same message. Hit up the server support to see if any issues on server side and after trying multiple things over past 3-4 hours nothing worked and now site shows this:
An exception occurred: [ErrorException] [E_WARNING] Cannot modify header information - headers already sent by (output started at /index.php:1) in src/XF/Http/Response.php on line 401
- XF::handlePhpError()
- header() in src/XF/Http/Response.php at line 401
- XF\Http\Response->sendHeaders() in src/XF/Http/Response.php at line 292
- XF\Http\Response->send() in src/XF.php at line 856
- XF::runApp() in iindex.php at line 23
- include() in main.php at line 15
- include() in index.php at line 55
What could have caused this error and how to fix this? Server support is out of suggestion other than to restore a backup from previous day.
