I got this error after installing tt-rss with all the default settings (connecting to the database using unix socket, with "ident" identification). I was able to fix it by doing the following:
sudo dpkg-reconfigure tt-rss
- During the ncurses install process I selected
tcp-ip as the connection method rather than socket and specified "localhost" as the server name.
- Then I told the installer to use
password authentication rather than ident
...and it worked! I am now able to reach the tt-rss web interface.
I looked really closely to the installer output of one of my installation attempts to use ident and saw an error that it is unable to create a local user account, so that's probably why the default options didn't work...
HTH!