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 ('3ae3aa0835e706b61d34f06803b17231', -1, 1711712863, 1711712863, '03ec8afd', -8, 0, 0)

Line : 187
File : sessions.php