Time Capsule 802.11ac not accepting disk password

Using Windows 8.1.

Through Windows Explorer, I used to be able to access my TC with no problems as either a network drive or a network location. Now all of a sudden, I start seeing a message asking me to input my credentials. My disk password and Wi-FI password both do not work here. I've suddenly lost access to the disk, and haven't done anything to cause it. Tried resetting both passwords in Airport Utility but still getting the same message. Any suggestions?

EDIT: Will resetting to factory settings erase the hard disk? I have about 400GB worth of files there that I cannot lose.