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 ('c6770874e3bebe97f71398d3e7d1df83', -1, 1711712965, 1711712965, '03523ad5', -7, 0, 0)

Line : 187
File : sessions.php