B Can Call A, but A Can't Call B

[edevic]

I have a problem with a new site. There are 5 total sites. For ease of explanation, A, B, C, D and E. B is a brand new site. Currently all sites can call all other sites with no issues, except when B calls A. When B calls A, neither end can hear the other end, but if A calls B, no problems. I have gone through all the firewalls involved and cannot find any issues. Other configurations details:
The Phones are 9204 in B and 9212 at A.
All phones at B are extensions from the server at C. Site E is configured this way too, and has no problem.
A has its own server.
Sites are connected with VPN tunnels. Sites C, D and E all have Sonicwall routers. A and B have Cisco RV042 routers.
B could not talk to any of the sites until I updated the RTP settings in the Cisco router. After this update B could not call A but A could call B. I also updated the settings in the Cisco at A, but it made no difference.
Anyone have any suggestions?