Calls using ZAP/DAHDI are not working

If you are using ZAP/DAHDI channels to make calls and experience problems with calls:
Calls hangup after 30 seconds or so
Calls are not connecting

And when you are connect to Asterisk CLI and see:

-- Channel 0/30, span 1 got hangup, cause 102

There is a problem with your provider, you need to contact them.