Error code 113 on home network

I've crawled through just about every post I can find about error 113, and have tried every step on Adobe's troubleshooting page for this specific error, but Creative Cloud is still throwing the 113 error when I try to update any of my apps.

Based on both the troubleshooting page and other threads on this error, I have tried: temporarily disabling my firewall, adding all Adobe programs to the firewall's allow list, temporarily disabling my antivirus and antimalware programs, clearing all of my Edge data, restarting in safe mode, restarting normally, and resetting my modem. I am on a wired ethernet connection and my computer does not have onboard WiFi (or one of those USB WiFi doodads). 

The only thing that I can come up with is having discovered that ports 80 and 443 are closed, which... I guess is the problem? However, I don't really know what this means, or how to fix it. I saw one solution in a thread on this forum that involved "creating custom inbound and outbound rules" for those ports in the firewall settings, which I attempted (?), but nothing changed so I can only assume I didn't do it correctly. 

I am absolutely tearing my hair out over this-- there's no network administrator or anything to pass this off to, so I'm at a loss.