Looks like account was last used about 4 months ago. When you create an MSDN forums profile it is associated to a microsoft account. The microsoft account is only used for the authentication method. You might be able to reset the
password for your microsoft account here.
https://account.microsoft.com/security
If you can't sign in then I'd work through this one or also chat / email support using the links at page bottom.
https://support.microsoft.com/en-us/help/12429/microsoft-account-sign-in-cant
Also the team foundation server forums have been archived here on MSDN. The discussions have been moved to StackOverFlow
https://stackoverflow.com/questions/tagged/tfs
Regards, Dave Patrick ....
Microsoft Certified Professional
Microsoft MVP [Windows Server] Datacenter Management
Disclaimer: This posting is provided "AS IS" with no warranties or guarantees, and confers no rights.