In this video we look at how you can soft reset either an Apple AirPort Extreme or Apple Time Capsule. You would use the soft reset option if you have forgotten the password to your base station, but you need to make changes or access the base stations settings.
When you complete a soft reset you reset the base stations password for 5 minutes, this will allow you to make setting changes and reset the administrative password to something more memorable. If you do not make any changes within 5 minutes the base station will revert back to its previous settings.
In this video we specifically show you how to soft reset an AirPort Extreme. However, the same process is used to soft reset an Apple Time Capsule.
Everything worked perfectly until I did the soft reset, at which point my Time Capsule logo in my Airport Utility simply went away, leaving me no way to request a passord reset.
It’s possible your Time Capsule has developed a fault, so when you perform a soft reset either the hardware or the software is not performing as it should.
If I were in your shoes I would probably perform a hard reset as according to Apple this will:
“Resets the base station to an unconfigured state, but retains the last saved configuration and any profiles, allowing you to restore your base station from previous settings. Perform this reset when the base station is unresponsive, or you’re troubleshooting network issues that aren’t resolved by other means.” – https://support.apple.com/en-gb/HT201945
However before performing a hard or factory reset, make sure that you have backed up any data on your Time Capsule to another drive. Hope this helps.