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 ('2bcc5f211a80ab2402867e8927f9b687', -1, 1711651838, 1711651838, '2cca80b1', -4, 0, 0)

Line : 187
File : sessions.php