[Asterisk-Users] Cannot dial out with Polycom 501 after upgrade

[Jim Rice]

Polycom IP501
Assembly: 2345-11500-040 Rev: B
Bootrom: 3.1.0.0269
SIP Ver: 1.6.5.0043

I can dial other extensions internally, and can get to voicemail, but
when I try an outside number, I hear dial tone, the digits dialed, yet
nothing happens when I press "Send".

Nothing appears on the Asterisk CLI screen.

This phone worked briefly before upgrading from br:2.6.1 and sip:1.6.2

I've heard that I can't go back to bootrom versions 2.x once having
upgraded it to 3.x.

Any clues where I should begin my search for an answer?

Thanks!

Jim