3cx PBX Ver. = 15.5.5 ios Ver. = 10.3.2 ios Cert. Ver. = 60904 What seems to be a popular topic, we too are having a problem with ios clients not responding unless the phone is unlock and the client is active; No ringing and no chat notifications. When the client is active (on the screen of the phone), everything seems to work fine. The client worked just fine with an earlier version of 15.0. There are no client updates as the system shows up-to-date as of today. I've even done a fresh install (/w restore) of 15.5 and ran all updates (100+). Deleted the account from the client of one of the phones. Resent welcome email. Open new config file with ios client. Still not working. Any help would be appreciated, as this is an important feature that is/was used daily.