Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed.
I was installing some deployments to three laptops; one of them had all the updates installed prior to joining the domain, the other two afterwards. We have PDQ Deploy and PDQ Inventory with server/client setup.
Got this error on the latter two laptops after some PDQ deployments, so the mechanism of PDQ was working but stopped working suddenly
Then restarted the PDQ Deploy service and the server and the deployments could continue.
Not sure if the update sequence had anything to do with it, might be coincidence.