Hi Janis,
thanks for your answer.
I’ve asked my new hosting provider (I recently changed it) and yes, my server is using ModSecurity… but it wasn’t the culprit. Apparently, my hosting provider defines an unusual temporary folder: /home/myusername/php_sessions/ instead of /home/myusername/tmp/ or /home/myusername/public_html/wp-content/temp/.
As soon as I created “php_sessions”, “save changes” started to work again.
Thank you again for your help.
Have a nice day!
