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 ('3e210b8944d86ceea907087444b5abbf', -1, 1545171624, 1545171624, '3693100c', 5, 0, 0)

Line : 187
File : sessions.php