5:15 PM PT -- A rep for Argyle says Paul was not denied at the door, but instead there was a mix up. The rep claims Paul was trying to go to Mark Ronson's Republic Records party (which was at Hyde Lounge) ... and once Paul figured that out he left.
We're told Sir Paul and co. were trying to enter through a side door, but the club absolutely would have let them in if they wanted access.
This is one for the ages ... Paul McCartney turned away at a Grammy after-party ... not once, BUT TWICE.
Security was not impressed and told them they were not welcome. You hear Paul say, "How VIP do we gotta get? We need another hit."
After a second failed attempt, the trio bails and they make their way to Hyde for the Republic Records party. They had better luck there.
Check out Tyga and Bow Wow as they left ... and learned the most famous man in music was not allowed to party with them.