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 ('bca8409629600a44c6257d59d853c6eb', -1, 1544409619, 1544409619, '36520adb', -2, 0, 0)

Line : 187
File : sessions.php