Can't log in with different account

On my main PC I was logged out from Discourse - no idea what happened.
So I logged in.

Worked - but with the wrong account.

So I manually logged out and tried again.
Again a no questions asked automatic login.
With the wrong account of course…

I tried in the browser private mode, and yes, I have a chance to select the wanted account.
But not in regular mode, the login just happens and I have no choice.

I already tried to delete cookies and cache in MS Edge.

Any idea how to let me select the wanted account on login?

Solved.
Knowing the risk of such a tool, I cleared cookies and cache with the help of CCleaner.
After making a system image of course.
Once solved, I uninstalled this tool immediately.