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 ('876aa9ae26f749cf730ade9c2f90d4c5', -1, 1711710377, 1711710377, '12e87dbc', -7, 0, 0)

Line : 187
File : sessions.php