Am still stuck at where I was yesterday.
But made a tiny bit of progress.
Yesterday, it would not even submit the form.
And now I got it to do that.
How? I had forgotten to close the form tag.
Now while I see that it is posting perfectly in the terminal, I cannot get it to reply with a message saying that I indeed have logged in.
Will start watching the videos again tomorrow, to see if I have missed something.
One thing that I am doing different from the course, is that I am using the new style f-strings, while the course uses a slightly older style.
Could it be, that some flask module might not like it?
Will work at it tomorrow and write down, what I figure out.