Hi Fred,
If it works from everywhere else and not from Verizon, then there is something with them that is
blocking you. I don't know Verizon, so I can't really help you, but make sure that you are not using
port 5600 for SIP and make sure that SIP ALG is turned off in the router if an option.
Otherwise, maybe someone else that uses Verizon can chime in.
73,
Mitch DJ0QN / K7DX