I am unable to complete this story mode because it keeps crashing. I have tried 3 times already. I will keep trying but I believe I will keep crashing. I am unsure what error occurs. I wasn't disconnect from server like the usual but this time the entire game freezes and crashes!

Have you attempted to run a file check? It will take a bit of time depending on the speed of your hard drive, but it will check for any corrupted files, which may be the cause of the freeze and crash.