I just added a phone to a norstar ics and assigned incomming ringing to that phone (multipl phones ring on incomming calls). No calls are handled by auto att. at any time, and at night the main number is forwarded to an answering service. My problem now is that when calls come in and ring more than 4 times thay are answered by the mailbox of the phone I just added. I checked all the settings I could think of, but can't find the cause of the problem. All calls should just ring untill answered, and it works fine when I remove line ringing from the problem phone. Any ideas would be great. Thanks in advance. And I thought I knew this system pretty well, but then things like this come up & humble me.

Remove call forward busy and call forward no answer....call forward no answer may be the only one assigned.