phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('491711ae731e6ea5e172e090ff7bc816', -1, 1711648878, 1711648878, '03ec13fb', -1, 0, 0)

Line : 187
File : sessions.php