welcome to the community.
If i have understood right, you have configured a static NAT for your Group 700 and PC with RP Desktop and trying to make a call via Internet. Do you use H.323?
I guess you have a NAT issue.
NAT question has been already discussed several times in the community.
Please, take a look at:
2) >>Administrator’s Guide Group Series 4.1.3<< p. 33 "Configure the System for Use with a Firewall or NAT"
and please check, that your firewall doesn't block any packets between units, it looks like a firewall block some h.225 messages.
Thanks for the reply, its working fine in LAN network. But unable to connect through mobile application using WiFi (Ruckus R510)in LAN network