That remind me of me but with English. I failed 3rd time and the only subject that hold me back. Just like internaldisputes said, depend on university's policy. If they care about money, as long you can provide, they allow you to continue. If they care about prestige, I don't think they allow you continue after 2nd time failing.

I know this is not what you ask but let me tell you about my experience. I dropped out after 3rd time but thinking back I realize that I can avoid that situation. My advice is, you should actively seeking help from your friends and lecturers. Ask them what you don't understand, even it is sound stupid. Engage more with your lecture of your subject so they can see your effort to improve yourself. Make extra time time you have to understand your subject theorically and practically. I'm sure you can do it, even if you're not socially good with people.