Lil Yachty seems to be responsible for getting his own concert canceled early this weekend -- because not long before the plug got pulled ... he was telling folks to come on down.

The rapper was performing Saturday night in Vancouver, BC ... and toward the beginning of his set at the University of British Columbia's Thunderbird Arena -- which looked to be packed -- the ticketholders could be seen pouring down onto the main floor and rushing the stage.

Take a look for yourself ... in footage obtained by TMZ -- you can see tons of young people descending toward the mosh pit area of the arena, seemingly at LY's behest.

Eyewitnesses tell us Yachty was shouting "fill it up" as he was starting to perform the very first song of his set list ... and his fans obliged, with tons of folks climbing over railings and security guards to get to the mosh pit area and be as close to Yachty as possible.

We're told Yachty did 3 or 4 songs under these conditions, but then his mic was cut off and the house lights came on. Someone over the speaker told everyone to go back to their seats -- something Yachty himself encouraged, saying the show would be over if they didn't.

Sounds like people didn't head back fast enough ... 'cause our sources say when Yachty trying launching into yet another song, the sound was gone -- and the gig was canceled.