Hi, I have the 3CX PBX for Debian installed. One of the extensions, which is provisioned to a Yealink T21P E2 phone, is going to DND status autonomously and no longer receives calls. Interesting is that the phone LCD screen doesn´t show the DND icon, but when I check this extension status using 3CX clients for another extension, the status is 'Do Not Disturbe'. If I restart the services on the server side nothing happens. If I press the DND button on the phone twice, then the extension status changes to Available. I updated the phone firmware, reprovisioned it and nothing. I didn´t find a pattern that explains this status changing, then I´m wondering if someone has experienced something similar. I have 4 extensions using 3CX clients and 2 x using T21P E2 phones. This status issue occurs only for the same extension. Thank you.