I have a user running VS 2015 trying to connect to our on premise TFS 2015 U2 environment. Other users are able to connect but this user is receiving the following:
Object reference not set to an instance of an object when trying to connect to the TFS instance. Won't even list the collections. I've verified he can ping the server, he can open tfs web access in IE. Any idea why this is occurring or what log I can look at on his machine that would provide more detail?
Try to clear the cache on this client computer:
C:\Users\username\AppData\Local\Microsoft\Team Foundation\6.0\Cache.
Disable the antivirus software or firewall to determine whether that change corrects the problem.
Use the IP address of TFS instead of server name if you have used server name.