The problem I see is that people don’t read these messages. They assume that
it is an error or something.

I think the text above (some different from a feedback message) is more
effective, and the extra field (username) helps on the differentiation. It
could be plain text instead of an input.

That doesn't make sense to me - if folks are not going to read an error message, they are certainly not going to read plain text that doesn't stand out at all.