I get gl error 0x505 (out of memory) when drawing elements for seemingly no reason. I have a lot of free GPU memory when this happens. Eventually, aftor a lot of this errors i get this crash: https://pastebin.com/8HDkqVqj. Please help.

Try running your program with https://github.com/LWJGLX/debug#how .
A crash in a draw call is in 99.99999% of the cases an enabled generic vertex attribute (via glEnableVertexAttribArray) which has no buffer source (via glVertexAttribPointer).

No, it's not  because of attribute. Debug addon prints: "failed to allocate memory for buffer object" when i try to draw buffer. Shouldn't opengl allocate memory when i invoke glBufferData?

Also if i look in task manager it says that gpu memory is almost free.