Had a coding challenge for an interview. 2 questions and I passed all the tests on both questions. But I got an email from the recruiter saying that one of my questions didn’t have a working solution??? Wtf it passed all the tests, am I retarded?

Can't be sure, but usually tests to pass are only "easy" part of challange. The code will be tested vs tests company does not provide, but have internaly. So maybe your code failed some of thier edge cases, do not know. But it's possible.

Personally, I would just brush it off and try with another company.

@NoToJavaScript yea that was my plan. I replied to the recruiter asking if I could get a copy of my code and the test inputs they used to see where I went wrong so hopefully they’ll send it. Don’t have much faith tho

It is still better than “we decided to go on with another candidate” and the day after they repost the job