Logging in with invalid user results in 500 error

[Perflyst]

I have a LDAP filter which checks if an account is active and allowed to login, e.g. following attribute: accountEnabled=TRUE

Therefore, if the user is not found, a 500 error (and a white page) is shown to the user.

2019/11/26 08:45:50 [error] 26359#26359: *27314524 FastCGI sent in stderr: "PHP message: PHP Fatal error:  Uncaught PDOException: SQLSTATE[22P02]: Invalid text representation: 7 ERROR:  invalid input syntax for integer: "Unknown User" in /var/www/tt-rss/classes/logger/sql.php:37
Stack trace:
#0 /var/www/tt-rss/classes/logger/sql.php(37): PDOStatement->execute(Array)
#1 /var/www/tt-rss/classes/logger.php(28): Logger_SQL->log_error('Unknown User', 'user', 1024, 0, '\nIP: XX.XX.XX')
#2 /var/www/tt-rss/plugins.local/TTRSS-Auth-LDAP/plugins/auth_ldap/init.php(84): Logger->log_error('Unknown User', 'user', 1024, 0, '')
#3 /var/www/tt-rss/plugins.local/TTRSS-Auth-LDAP/plugins/auth_ldap/init.php(346): Auth_Ldap->_log('user', 'Unknown User', 1024)
#4 /var/www/tt-rss/include/functions.php(543): Auth_Ldap->authenticate('user', 'pw123...', false)
#5 /var/www/tt-rss/classes/handler/public.php(661): authenticate_user('user', 'pw123...')
#6 /var/www/tt-rss" while reading response header from upstream, client: XX.XX.XX, server: tt-rss.domain.tld, request: "POST /public.php?return=https%3A%2F%2Ftt-rss.domain.tld%2Findex.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php/php7.3-fpm.sock:", host: "tt-rss.domain.tld"