Caller ID has suddenly started to display 'External' for all calls
Caller ID was working OK this morning.
Since this afternoon it now displays 'external'
This happened to me in June 2018 as well (except that it was only 50/50 displaying incorrectly.
In that case it needed an engineer to sort out something at the local exchange
Have dialed *234# and the message is that 'caller id will be displayed' but further calls are still displaing as 'external'