Comment 17 for bug 1431305

Could have been that the debug marks interrupted the askpass process.

It sometimes happens that pw-cache doesn't collect the passwords on startup and so only return empty strings. I'm neither yet sure why this happens nor can I just say empty string is invalid and do it again because if you have a passphrase-less key the string must be empty.

If this happens again it should help to run 'backintime --pw-cache restart'

Some versions of python3-keyring do have kwallet and Gnome-keyring support integrated. For others we need to install either python3-keyring-kwallet, python3-gnomekeyring or python3-secretstorage. Where python3-secretstorage is a method to access both kwallet and Gnome-keyring. This depends very much on the distribution and release. You are fine without all of them because it is integrated in python3-keyring