Do I need to use a full FQDN on a phone when using V18?

[greychain]

Recently a customer upgraded to V18 and phones were no longer able to connect to the server.

Previously they had only been using the host part of the FQDN. The phones will connect using IP.

Any thoughts?

 

[Saqqara]

You have to use the full fqdn , not the host part - this has always been the case

If they had been using fqdn internally , when you run nslookup fqdn does it resolve to the 3cx server. You may have to change your internal fqdn dns record

You can use both fqdn or ip internally , if you use fqdn you can change the IP address of the 3cx server - you just change your internal dns fqdn record , where if the phones are using ip you have to factory default the phones