Issue with Q.850;Cause=16

[jsplamondon@secur01.com]

Hello, I'm not sure I’m posting in the right thread if not move it to the right place please
A client is having an issue here and there about Q.850;Cause=16. I've researched on the error, it means

Quote:Cause 16 Normal call clearing - This cause indicates that the call is being cleared because one of the users involved in the call has requested that the call be cleared. Under normal situations, the source of this cause is not the network.

After maybe 15-30 minutes without doing anything, the message disappears and the client is able to make outbound calls again.
I'm wondering what exactly could create this problem and how to solve it instantly when it appears or just disable it.
Thank you!