7:45 PM PST -- A rep for Lil Wayne tells TMZ the rapper didn't walk offstage because of the crowd, he was frustrated because the venue experienced technical difficulties and there were problems with his mic. For the record ... it was a sold-out show.
Lil Wayne just gave up on a crowd in Italy ... throwing his mic and walking offstage after they failed to get behind his performance.
Wayne's overseas for Milan Fashion Week and was performing during the Philipp Plein show, you can tell from the video ... the crowd just wasn't feelin' it. At one point, the rapper tells everyone to put their hands up -- and with the exception of about a handful -- no one listens.
It's unclear if there was some type of language barrier or if the folks in attendance just weren't Weezy fans but one thing was for sure ... the rapper was PISSED, throwing his mic and walking off.
Lil Wayne ... he's not for everybody.