I am currently playing as a mage and sometimes when i cast one of my spells , it uses mana but doesn't work.

Let's say my mana pool is full.

I cast one spell and it doesn't work but uses mana ( projectile completely misses its target)

Second one doesn't work but uses mana ( summon effect appears but nothing happens)

Third one works ( lol )

Fourth one doesn't work but uses mana ( character raises his hand but nothing happens )

In the meantime my enemy beats the *** out of me.

Long story short, when i cast my spell, it uses mana but doesn't work.If i cast it 3-4 times in a row, third or fourth one works but i use all of my mana to cast 1 spell.This is really annoying you know, i don't know why this keeps happening but it really makes me angry.