I had this question after viewing "Incorrect Username or Password" on log in
After setting up a new VoIP phone system from Comcast Business on our network, which required re-configuring our Dell network switch with VLANs for voice and data, we started to see issues with users not able to login to the network even though their credentials are valid. I would like to know if others have a similar experience and if so what is the best solution to avoid this kind of problems. Also, I am still trying to resolve the login problems for the users and the only way I have been able to use thus far is to have the user reboot their PC and then they are able to login again. I had similar problems with my domain admin account randomly on different servers. Why is it that on some servers my login works and others it does not?