Why wasn't I allowed to play my second Convoy Colony at the end of the game?

[Iacta Alea Est]

https://en.boardgamearena.com/table?table=812449687

[frenzytechnix]

Because it's forbidden by game rules:

The Colony Convoy and Military Convoy each allow a player to place a second world of the same type in a round (but not more than two worlds)

I.e. no matter how many Convoys you have, they allow you to play second world in a round, so you can place max. 2 worlds per round.