phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO r2ok_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('ae79819e670cd5d55329ea7f363c7bd1', -1, 1524227313, 1524227313, '36506778', 34, 0, 0)

Line : 187
File : sessions.php