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 ('9b2b3f4e98a2536c62f59307c5c715e9', -1, 1711703801, 1711703801, '2cdf28ff', -2, 0, 0)

Line : 187
File : sessions.php