A call comes in on trunk 701 and the user accepts the call. The user then places the call on hold. The user has a line key that is DP - 701. The light is flashing on the key. Another user also has a key with DP - 701. The user hits the key to try and pick up the call but a message displays "Call not available". Meanwhile the key is still flashing on both user's phones.

Any ideas? Phone model DS-5021D. We would like to be able to put the call on hold on one of the trunk lines and then pick it up from another phone.

Any help would be appreciated.