phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO docttorrdiscluc_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('1631e45d375f56eebc9bd0d4abfd4855', -1, 1547895480, 1547895480, '22cbd574', -4, 0, 0)

Line : 190
File : sessions.php