phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('26685721d13488823347ffcce531cfdd', -1, 1550865945, 1550865945, '6b17b0a2', 21, 0, 0)

Line : 189
File : sessions.php