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 ('491ee9e8455506ea4d8829611f7d57ae', -1, 1711711834, 1711711834, '22e7f7fe', -9, 0, 0)

Line : 187
File : sessions.php