This is not a duplicate question, I've followed the steps in the similar question that was posted on Ubuntu v. 18.04, but no solutions worked.
sudo dpkg --add-architecture i386
this is returned when I try to install i386 packages or after updating the list.
E: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/hirsute-security/main/binary-i386/Packages 404 Not Found [IP: 126.96.36.199 80] E: Failed to fetch http://ports.ubuntu.com/ubuntu-ports/dists/hirsute-updates/main/binary-amd64/Packages 404 Not Found [IP: 188.8.131.52 80] E: Some index files failed to download. They have been ignored, or old ones used instead.```