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 ('2da1c5c8e7d05548452912623a737f4c', -1, 1711696707, 1711696707, '36910c1c', -4, 0, 0)

Line : 187
File : sessions.php