404 Error Page not working

[FlowJow]

Hello to everybody,

I have inherited the website of our dance association. It works fine and I was able to update it to the latest Process Wire version. Our webserver runs PHP8.3.

Strangely, I do no get the 404 error placeholder-page for undefined pages to run. I use the newest .htaccess and the page exists in principle. However, without debugging mode, the site does not arrive in my browser. I only get:

Quote

Die Website ist nicht erreichbar

Die Webseite unter ... ist eventuell vorübergehend nicht verfügbar oder wurde dauerhaft an eine neue Webadresse verschoben.

ERR_FAILED

https://i.ibb.co/0n16KpV/404-error-pw.png

When I set debugging mode active, then I am able to receive the pre-defined 404 error page in the following way:

• Open the website that not exists like /unknown => I get the abovementioned "Webpage not available - ERR_FAILED" form Google chrome
• Press CTRL+F4 => I get the 404 error page from process wire
• If I then refresh normally with "F5"  => I get again the abovementioned "Webpage not available - ERR_FAILED" form Google chrome
• I seem to only be able to get the page when I press "CTRL+F5". Realy weird.

Do you have any idea what I can do or how I could debug it? I do not get any warning or log that helps me find the root cause of the problem.

Thanks in advance and Best Regards

Florian

 

 

 

 

[FlowJow]

Actually with debugging active now I get the following warning shown:

Quote

Warning: preg_match(): Compilation failed: unmatched closing parenthesis at offset 20 in /www/htdocs/xx/xx/xx/wire/core/Template.php on line 904

Warning: Cannot modify header information - headers already sent by (output started at /www/htdocs/xx/xx/xx/wire/core/Template.php:904) in /www/htdocs/xx/xx/xx/wire/core/WireHttp.php on line 1823

 

+When I install the process wire fresh with the basic empty template I can see the 404 error without any problem.

[BrendonKoz]

Things I would consider trying first if I ran into the same problem:

1. What is different between the current website, and a fresh installation of ProcessWire? (Can I take a DIFF of the core files [wire folder], index.php, and .htaccess?)
2. Has the current website used any modules that attempt to capture 404 responses that is causing an issue?
3. Are either instances being run from a subfolder, or are they installed in the root?
4. Are they running on the same webserver (eg: NGINX vs Apache 2.2 vs Apache 2.4 vs Litespeed)
5. Does the webhost have any services in use that might cause unexpected issues (ex: mod_security)
6. If I were to check the web browser's debugging NETWORK tab, is there anything I can see different from when it shows the expected page vs when it does not?

I'm sure there could be other things I could try too, but those are what I think I'd try right now.