I randomnly see the error on different domains. I have googled and tried different solutions but none removed the problem. Now I try to reproduce the error to find a solution - but I cannot reproduce!
This is the access log and error log in case of an error:
xxx.xxx.xxx.xxx - - [25/Nov/2021:18:43:33 +0100] "GET /humans.txt HTTP/1.1" 406 - "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36"
[Thu Nov 25 18:43:32.999114 2021] [negotiation:error] [pid 1305749] [client xxx.xxx.xxx.xxx:63157] AH00690: no acceptable variant: /usr/share/httpd/error/HTTP_NOT_FOUND.html.var
...and this is the access log when I try to reproduce the error:
yyy.yyy.yyy.yyy - - [26/Nov/2021:08:52:45 +0100] "GET /humans.txt HTTP/1.1" 404 1110 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36"
Of course I tried browser identifications and different languages that are supported by my server and ones that are not supported. But everything works as expected. If I use a language that is supported the error message is displayed in the language, if the language is not supported I see the english version. How can I determine what calls/settings leads to the error?