Maximum number of photon cannons?

Is there a maximum number of photon cannons and if so what is it. Me and a friend were cooping and playing the stop the warp prisms from escaping mission. We were playing Artanis and Vorazun, and he placed a lot of cannons and eventually couldn’t place any more.
Is this a glitch or is there a limit to the number of photon cannons a player can make.

In very early LOTV I just playing on my friends account and filled a map with cannons in PvT. I literally filled the map. Best part is I lost because I was trolling too hard. That poor guy had to clear the entire map of cannons with nukes and tanks tho. That’s 1hour either of us will never get back.
The limit is how many minerals are on the map.