my standard answer:
- create a complete backup of the 3CX
- save the backup outside of the 3CX
- make sure it is complete (extracting it correctly should be enough)
- make a copy of the backup
- open the copy with Windows Explorer (for example)
- extract the XML from the compressed file
- edit the XML and replace the 3CX FQDN in all places
you may need to adjust the FQDN in some other places, like databases in the backup, YMMV
you may need to adjust other licensing information as needed, this depends on how it's configured by 3CX, you may have to experiment
- drag the edited XML back into the backup
this ensures that the backup is not discarded when 3CX is restored
the way the file is assembled is important, simply unpacking and repacking all together won't usually work
- reset 3CX:
Debian - start /usr/sbin/3CXWizard -cleanup on the shell
Windows: remove 3CX, delete the directory below ProgramData, reinstall 3CX
- unlink your license from the old FQDN in the 3CX portal
- maybe: start the 'install' for your now unlinked license with the new own FQDN in the 3CX portal so 3CX knows about the binding between your license and the new own FQDN, this creates a setupconfig.xml which should be unneccesary
- start the 3CX First Time Setup Wizard, give it the backup and give it the certificate files if you use your own (you should have them)
- set the ports back to how they were before
point 7 is it
With a little more effort, you can change even more things: system owners, passwords (or hashes), the license key, email server and so on.
Even though 3CX doesn’t officially support this, these possibilities still exist. Whenever I’ve actually helped someone with something like this, I haven’t published it in the forum - since now