The problem you had with the spray can paint is not uncommon these days, even for regular-old rustoleum. I had the same thing happen when painting an
oil pan. Had to scrape, sand, and start all over...
If you look at the directions, it will probably tell you to add second coats some minutes after the first coat. It will also likely tell you that if it has dried, then you need to wait maybe two weeks before repainting. That is what I found after reading the directions during my debacle.