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 ('78c28b30a3e557267ca954b552ae828b', -1, 1544406549, 1544406549, '345b5a7a', -1031, 0, 0)

Line : 193
File : sessions.php