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 ('c9438192d3412e121fce2ee16d4851ef', -1, 1558249977, 1558249977, '22e54cc1', 6, 0, 0)

Line : 187
File : sessions.php