Thanks RonR. No, I could not make a call using the **8 - I got the same error message. However, I think I got it fixed.
In Obitalk portal, went to Physical Interfaces -> PHONE
Set CallReturnDigitMaps = ...,{li:(<**1>xx.)}, instead of default value of ...,{li:(<**8>xx.)},
That's the advice I was given. Not sure why it worked.
However, I'm noticing a different problem associated with using the line port. Now when I answer a call I hear complete silence for the first 5 seconds followed by a short tone and two beeps and then I can hear the other person. It happens consistently when I have the line port connected. Doesn't happen at all when I disconnect the PSTN line from the line port.
Have you had this experience? Any ideas how to fix?