This question has been asked before but I did not solve my problem and I getting some weird functionality.
If I put my index.html file in the static directory like s
index.html should be inside templates, as I know. So, your second attempt looks correct.
index.html
templates
But, as the error message says, index.html looks like having some errors. E.g. the in the third line, the meta tag should be actually head tag, I think.
meta
head