Note on using Microsoft Office 365 Teams together with Visual Studio and IIS Express

Microsoft's Office 365 is a great suite of productivity tools on top of a cloud-based service. I'm a fan of the Microsoft Teams application, which could be called as an "enterprise collaboration and messaging tool". However, it turns out that Teams reserves around a dozen of TCP ports for itself. This in turn can conflict with Visual Studio's ASP.NET web application debugging when using IIS Express (or any other application for that matter).

You might get errors similar to this:

IIS Express Notifications
The specified port is in use
Port '1234' is already being used by process 'teams.exe' (process ID '12345')

In this case, either close Teams temporarily, or adjust the port your web application is using.