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 ('224ea2a613960422f374c62e78c4e1c3', -1, 1513306122, 1513306122, '365acf4b', -10, 0, 0)

Line : 189
File : sessions.php