[NSFW] admin login problem

This site and login were working fine since several years. Suddenly, the admin login does not accept my credential. When I use the (Lost your password?) and enter my account email, I got the following error (Error: The email could not be sent. Your site may not be correctly configured to send emails. Get support for resetting your password.)

I self host this site on AWS Lightsail. So, I connect to my instance using the browser-based SSH client, and got the (user) bitnami_application_password, and try to use it in logging with it, it does not go.

The page I need help with: [log in to see the link]