VLAN for 3CX phone system connected to Cisco catalyst 2960x, Watchguard M370 for DHCP

[bfordz]

I have a Watchguard M370 running Fireware 12.4.1 connected to Cisco catalyst 2960x switches.
We're adding a new phone system; 3CX server with Grandstream IP phones.

I added a 3rd VLAN(50) to my Watchguard to do the DHCP for the phnone network on Interface 6 (as a VLAN interface).

I was wondering if someone could me the correct set up I need in both the Cisco switches and my Watchguard to make all these talk to each other and make this work.
My trusted network (Pc's) that will be getting attached to the phones run static IP's on a separate VLAN.

What I have so far:
WG M370 Interface 6, Trusted VLAN(50)-172.06.50.1/24 doing DHCP-172.16.50.100 - 172.16.50.199
WG Inf.6 connects to Cisco Sw1, Port 43-Trunk port with VLAN 1 and 50.
-VLAN 1 trusted network - 10.249.115.1/24
-VLAN 50 trusted phone network - 172.16.50.1/24

3CX switch/server (static IP 172.16.50.10) connected to Cisco Sw2-Port 11 - Trunk Port with VLAN 1 and 50
my Grandstream test phones are plugged into Cisco SW2 - ports 12-14 - Trunk Ports with VLAN 1 and 50

My phones are getting a VLAN 50 IP address, I can call the individual phones but can't make an outside call.
If I setup a Pc on the VLAN 50 network I don't see traffic trying to go out; based on my WG M370 logs.

I'm new to VoIP phones and getting them to work with Cisco and Watchguard.

Any help or suggested would be appreciated.