I was like this when I was in college. After the graduation thesis is written, the teacher in charge of taking you will check it, put forward some problems in the thesis, and then make a graduation defense after revision. There are usually several teachers in the defense. So if the first defense fails, There will be a second defense in the next few days.

If the second defense fails, Can't get a diploma. I have to wait for the next graduating class to make a graduation defense, and I am defending.

I hope it helps you. Thesis is actually not that difficult. Come on!