That’s a tough one.
Basically the app is a proxy for the official Bitwarden CLI, so you might try whether it works for you when you log in from CLI?
The command the app uses:
bw login [email] [password] --raw
or
BW_CLIENTID=[clientId] BW_CLIENTSECRET=[clientSecret] bw login --apikey
The bw (if you installed it through the app) is located at:
~/.local/share/harbour-bitsailor/harbour-bitsailor/bin/bw (I’m not 100% sure about the bin/bw part but if it’s wrong, it should be easy to find it in the directory).