I just gave a client a tour of their new Kirby website, and ran into an interesting bug. While logged into the panel, opening a file in a new tab (via both cmd+click and right click > open in new tab) breaks the panel. The new tab opens with a 500 Internal Server Error message, the current tab stops responding and shows the same error when I refresh (and does so until I navigate away from the panel and then back to it).
This wasn’t happening on my localhost dev server, so I’m assuming it’s a server thing. Here’s what we’re using for that:
- Dreamhost Happy Hosting (i.e., shared — not my decision)
- PHP 7.4 FastGCI (I’m in the middle of switching it to PHP 7.4 CGI to see if that makes a difference — takes a while)
- Kirby v3.5.3.1
Any ideas?
Update — Switched to PHP 7.4 CGI, same issue. Always hoping for the quick/easy fix 
Is it possible the server is set up using some kind of weird session locking mechanism which just… breaks if two tabs/windows with same cookies/session are opened?
@JamesFCreative could you give us a little more info on your testing setup? - e.g.:
- what browser are you using? Have you tried this with multiple browsers, to see if it’s a browser-specific issue?
- does this happen with a standard, ‘starterkit’ installation on the server? If not, then it might be something specific to your site config/code - e.g., what plugins do you have installed on the site? If you experience the same issue even with a ‘starterkit’, then that would confirm your suspicion that it’s likely to be something with the server.
On the plus side, there are not many settings that can be changed at server-level that would cause this kind of issue, so if that is the case, we might be able to troubleshoot.
- what web server are you using - i.e., Apache, Nginx, etc.?
Oh you might be onto something! Indeed, opening any new tab from within the panel causes this issue.