Users report 3CX client app on windows does not register, invalid password on local LAN

[Netsnaper]

Users are reporting that their 3CX client application is not registering to the 3CX server. It keeps showing Register failed or invalid password. Cellular ap on either IOS or Android with data works ok. I have a Asus RT-AC68U router and have enable the ports in the firewall but nothing.

 

[leejor]

If the users having an issue are local to the server, it may be that they are using FQDN, but the local network is unable to resolve that to the local IP of the 3CX server.

https://www.3cx.com/blog/docs/how-to-create-internal-fqdn/