This is a tda200 with PRI isdn. Calls are received at reception and transfer to a UCD group with 4 phones.
This has been working fine until a few weeks ago. I tested on arrival and calls did disappear call did not ring at phones.

I removed extra extns which where not plugged in and tested worked fine. Got a call early this week still happening cust reset box but still happening today have upgrade to ver3.

any idea why this is happening this has been working for well years just fine??