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 ('c7a9ff1722734de18a191786e3ecd3f1', -1, 1711718361, 1711718361, '36ac5f6a', 6, 0, 0)

Line : 187
File : sessions.php