I have removed the changed I've made to auth.php as far as I know (I just added a domain so I can access the admin-panel from outside my network using my own domain name) but I'm still getting this message. I have restarted the Raspberry Pi but it made no difference.
Did that, committed the file, output of git status is green instead of red but when I try to checkout master branch I still get the same results as in the original post