I would recommend being very careful about what is changed in the WebServer because 3CX uses that heavily for most of the functions it initiates, ideally not touch it at all. One slight mistake and most things will not work. The bad thing about this is that 3CX Support will also not fix it for you, they will instruct you to make a Full Backup (if you can get into the Management Console and that isn't broke), uninstall, re-install and go again.
Also I must let you know that Abyss is a bit 'picky' with what you change...