KX-TDE100 VPN

[AllCommSolutions]

I have a KX-TDE100 with KX-NT366 phones, with two new phones at a remote site with a VPN connection between sites. The phones work in all ways, except cannot be heard on outgoing calls, intercom or CO calls. Outgoing audio from either speakerphone or handset does not work, although incoming audio is fine through both. They just act like the microphones don't work, but when connected at the PBX site, phones work fine.
It appears that it may be an internet VPN issue.
Any ideas about what to check? I am stumped.
Thanks in advance.

 

[obtsystems]

make sure both ip address on the system can be pinged from remote site.
is the VPN firewalled

 

[AllCommSolutions]

Thank you for responding. Good point. I will ping test everything again, especially to see speeds. As for the firewall, I don't believe so, but we are using Cisco RV042 VPN routers on both ends. I am just learning these routers.
For clarity, everything on the phone sets works, except outbound speech (ie: when calls are placed, we can hear the called party, they can't hear us.) There appears to be a latency issue.