routing to classic extensions not working anymore

Hi

I have several classical extensions configured to which calls can be forwarded. Both by the digital receptionist or if no answer.

I noticed that this functionality has suddenly stopped working while I have changed nothing in the configuration. All routings to classical extensions trigger the system answer that the destination cannot be dialed. No matter if the routing was dialed by the digital receptionist or direct from the incoming routing settings. The system log gives the following error:
app_dial.c: Unable to create channel of type '' (cause 66 - Channel not implemented)

The extensions itself seem to be working fine as I can dial them direcly with their extenion number? What can be the reason of this error?

Regards
Fred

This post has been edited 1 time(s), it was last edited by fre on 15.11.2013 at 13:51.