I've written a question for Chemistry SE but get "Your question couldn’t be submitted Resolve 1 issue before posting". This is the title which I've reworded a number of times without meeting tje hidden/unknowable requirements and is currently "What might stop bismuth crystals from being iridescent?" which seems like a perfectly valid question to me. What am I, or SE, doing wrong?
To wrap the comments up, you commented
I think it didn't like my tag "bismuth"
and this tag issue was the reason. The system were declining your question because you were trying to create a new tag without having 300 rep points.
In the future, please refrain from creating tags for the chemical elements: these are useless because you can find all relevant posts simply by searching for this element's name. Introducing new tag also should ideally begin from asking whether it is reasonable on this Meta, and if you don't have enough reputation, proposing a new tag by creating a request by starting a new discussion on Meta is the only way. A well-written summary can be found on SO: When is it appropriate to create a tag, and how does it work?