phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO satshop_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('c73738f7be6b06548e3ed07fa8c4cc22', -1, 1728659157, 1728659157, '2cc87ad6', -4, 0, 0)

Line : 189
File : sessions.php