When forward to PO/Attendant 4059 => communication broken

[Czar666]

Hi,
I have an issue in a company who is forwarding a ip phone to the 4059.
If 4059 is free => then everything ok, call is forwarded and person can answer the forwarded call.
If 4059 is busy => call is broken after few seconds (you just can hear the welcome message). In fact communication should go to music on hold.
Anyone an idea where I have to start searching?
Thanks in advance.

[vad]

What about usual incoming calls to attendant - no problem with free or busy state?

[Czar666]

Hi Vad,
Thank you for your reply. I asked the customer to do this test this afternoon. I'll keep you informed about the result.

[Czar666]

Customer replied that it works again.
Thanks anyway for the help.