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 ('01742c5b8d4d30b56ecd9d3c88beb5d8', -1, 1531905318, 1531905318, 'c0a865fd', -1, 0, 0)

Line : 187
File : sessions.php