Did you change your router or has the router firmware been reset to defaults? Check SIP ALG (must be off) and port forwarding rules (RTP port range must be forwarded to UCx).
Or possibly, has the public IP address used by the router changed? Go to SIP Settings and try Auto Configure to see if the detected address is still the same.

Hey ucxguy, Thanks!! I did perform the auto config it populated all the parameters. I noticed that the gateway address was different so I put in the correct one and I am able to make calls and both parties can hear. However, I am still unable to receive calls.. I had this same problem some years ago and new rules were applied.. I'm wondering if there is an issue with either a rule or maybe a wrong address somewhere.. I disabled the firewall and still have problem but it seems as though something in the system is not allowing for incoming calls...

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Voice Connect Plus, Inc.
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A common reason for not receiving incoming calls is a mismatch between the point of presence (POP) configured in the VoIP.ms configuration and the one to which UCx is connected. Make sure you use the POP from VoIP.ms configuration in the UCx trunk configuration.

Sometimes Voip.ms will reroute traffic through another POP.
In the trunk peer details are you using a FQDN or IP address for the host.
If using an IP and then Voip.ms does a reroute you will get inbound failures

Thanks to all of you. We have resolved the issues by disabling the firewall in UCX and rebooting system. Everything works the way it should now..

www.voiceconnectplus.com
Voice Connect Plus, Inc.
have a great day and a better tomorrow