I had this problem over the last few days too, and someone finally found a solution that works.
- Go to your OneDrive account at https://onedrive.live.com/ . If it's frozen due to you having exceeded your available storage space, that's the problem.
- Delete files or purchase more storage space until you're below your storage limit.
- Wait 12-24 hours for the system to automatically unfreeze your OneDrive account. It won't unfreeze right away, even if you're well below the storage limit.
Once that's done, your Bitlocker page should work again. Don't ask me why, all I know is that it worked for me.
I hope this works for you too!