Call destination cannot be resolved

[clivecarter332]

I have A Grandstream IP phone set up as ext 2002
I have Voipuser and voiptalk accounts
Both are registering ok, and providers status pages also show I am registered

Trying to ring in results in following in log

22:00:21.609 Incoming c8 "007789937138"<sip:[email protected]> <sip:[email protected]> Incoming call (before routing)
22:00:21.609 Incoming Call from line [#08444844790 @Voipuser]
22:00:21.609 Current route target for line [#08444844790 @Voipuser] is not registered at this moment
22:00:21.609 Rejected c8 "007789937138"<sip:[email protected]> <sip:[email protected]> Call destination cannot be resolved
22:00:21.609 Terminated c8 "007789937138"<sip:[email protected]> <sip:[email protected]> Call ended

(Note, I have tried registering the voipuser account with an external number of 448444844790 and 08444844790. Registers ok in both cases,
but still get same error)

Anyone know what I have NOT set correctly ?
Clive