Thanks Clowrym, i thought it had to be something fairly simple. The log now shows that the port is open, however the GUI doesn't come up...any thoughts?
CONFIGURING PORT FORWARDING
Transmission startup script complete.
Wait for tunnel to be fully initialized and PIA is ready to give us a port
Fri Feb 8 17:29:13 2019 Initialization Sequence Completed
Generating new client id for PIA
Got new port 21613 from PIA
transmission auth required
localhost:9091/transmission/rpc/ responded: "success"
Port is open: Yes