Problem with "Value cannot be null. Parameter name: key" in tfs site server

Question

I have a problem with my site TFS when I click on my project on site:

Value cannot be null. Parameter name: key

I tried to find a solution to fix, but couldn't. I hope that anyone can help me.

Thank you very much and regards.

Answer 1

We had the same issue, turns out there is a problem with the latest version (2.0.3) of the vsts-team-calendar extension:

https://github.com/microsoft/vsts-team-calendar/issues/260

"As soon as this extension was pushed out, all the Team Projects disappeared from the web portal in the project collections with the extension. You will get an error on the page, "Value cannot be null. Parameter name: key". Other project collections without the extension work as expected. Disabling the extension will resolve the problem."

When removed, problem was solved.