[2019] Inventory is full with only 4/30?

This is probably a noob question, but I've tried googling and searching the subreddit and can't find an answer. I cleared an enemy control point and found a blue crate that's lootable, but for some reason it's saying my inventory is full.

I've checked my inventory and dismantled anything I'm not currently using. It says 4/30 Inventory at the top. Why can't I loot this chest and how do I make more inventory space for it?