The operator reported that she cannot make an outgoing call from the list of missed calls on the Grandstream GXP1620 IP phone, the phone display shows “No suitable dialplan”, but if you dial the number manually, the outgoing call is made, a similar problem may occur on other models.
To debug, I connected to the Asterisk console and asked the operator to make an outgoing call from the missed list:
asterisk -rvvv
As it turned out, the call doesn’t even reach the Asterisk server, so I used TeamViewer to access the web interface of the operator’s IP phone and after a few minutes I discovered that Grandstream phones have their own local dial plan, which can be seen in the Account 1 -> Call Settings: Dial Plan menu:
{ x+ | *x+ | *xx*x+ }
It only allows numbers that consist of numbers or start with *. When the operator dials a number manually, it consists only of numbers, so the call goes to the server, and in the list of missed numbers at the beginning there is a country code with the + symbol at the beginning, so the call is immediately cut off and not sent to the server.
To solve this problem I changed the dial plan to the following (you can also just clear it):
{x+ | \+x+}
See my other articles about Asterisk