Call drops after 15 seconds

THis is a weird problem that has been a pain.

  1. I use smb 4.5
    2, Have have a network on
  2. I have a VPN on

All the phones in the main network work just fine.
I have one remote phone on the VPN network.
It registers, I can call out, get calls in and use the paging functions.
It rings, shows all the other extensions and shows me when those extensions are in use

THe problem is that the phone hangs up after 15 seconds and I cant find anything that causes it.

THe phone is a grandstream gxp2020. I also can not seem to set more than a 3 number password on any of the grandstreams. (12 phones)

Please help.

If there is a local Van Nuys tech, I would be happy to pay to fix this!

The local network phones are and the VPN phone is

also even though the remote works, it is registered but also says “Network Down”

Problem Fixed

I found the
Additional Local Networks

Under network setting, advanced settings. I added and it no longer drops the call.

It still says “network down” on the phone and I can not access the smb server using the local IP# form a vpn computer.

ANy suggestions?