Trump says they're negotiating, Iran says they're not. So either:

A) They are negotiating and it was supposed to be a secret but Trump blabbed

B) They aren't negotiating and Trump thought he could just lie and Iran had no way of disputing his claim

Both seem plausible, but I'm kinda leaning towards B. Trump has consistently shown that he doesn't think Iran has any agency here, and so far he's been proven wrong.