To use it, you need to go to Actions -> Configuration, in TTRSS web interface and select "Activate API".
Then, in your android ttrss-reader, fill the TTRSS server adress: "https://yourdomain.org/ttrss", username, password. (no need to use HTTP authentification)
**Note** : you may need to desinstall and reinstall the TTRSS application, through the Yunohost admin panel in order to be able to connect.