My boss won't take calls, what reason do I tell the caller, this happens daily.?

Question

My boss won't take calls, what reason do I tell the caller, this happens daily.?

Answer 1

Just say "He is not available at the moment".  No need to detail why, keep it simple and take a message.

Answer 2

I would say something like, "Mr. McWaddles isn't available to come to the phone right now, but I will be sure that he gets your message".

Then it's up to him to decide whether to call back.  It's not your fault if he doesn't.  You work for him, not the caller.