Here’s a cute one: after a period of inactivity the CX600 signs the user out and shows the following error:
“Sign-in Error. Account used is not authorized. Please contact your support team.”
The weird thing here is that the phone’s tethered to the PC, and the user has a csClientPolicy that disables Hotdesking. So why’s it logging itself out?
This turns out to be a problem I made for myself: the customer had me change this from a csCommonAreaPhone to a standard user phone (i.e. remove-csCommonAreaPhone, then tether). This all took place remotely, so I never power-cycled the phone, and hence it ended up not knowing if it was Arthur or Martha: tethered to a PC as “Better Together”, but still thinking it was a common area phone with Hotdesking enabled.
I had this happen repeatedly with a handful of phones (all of which we’d “re-purposed” as above), and the fix was a factory reset. (Hold 4&6 while you power cycle it). A plain old restart might have cured it (or flush all user data with *&#), but by this stage I wasn’t taking any chances.