Incoming Calls

I'm having issues with incoming callers not being able to hear me. I have the grandstream ht502 running behind my router. I have a static IP set on the HT502 with port fowarding setup on my router. It seems like whenever I have a issue it is on the weekend when I can't contact support. Last weekend I had a issue of incoming calls going straight to voice mail. I resolved this by rebooting the ATA. I guess a support call Monday is in order, but meanwhile does anyone have any suggestions?

Here is how I have the ATA and router setup:

Static IP setup:
Selected Statically Configured As
Assigned IP address of: 192.168.1.151
Subnet Mask: 255.255.255.0
Default Router: 192.168.1.1 (Linksys wrt54gl)
DNS Server 1: 156.154.70.1 (default from VOIPo)
DNS Server 2: 156.154.71.1 (default from VOIPo)

Ports 5004-65000 (UDP) were forwarded to 192.168.1.151 in Linksys WRT54GL router

Thanks for any help!
Steve