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 ('1e4c0b6112526c1a0e3a78b1ce908bd7', -1, 1540330739, 1540330739, '36e0387e', 6, 0, 0)

Line : 187
File : sessions.php