tritch,

Thank you for your response. You didn't explain why it sounds to you as port blocking issue - and I can't think of any reason (given other data points that I listed: calls to the other SPA phone port go fine, and calls to Voipo-provided adapter go fine as well).

Regardless, for last two days the incoming calls come fine; so it sounds to me that Voipo fixed something on their BYOD server. If the problem starts again, I'll continue the troubleshooting.

Thanks again for trying to help.