Hello dear SL Users,
I was directed here from the scientificlinuxforum.org because I seem to have encountered unusual behavior of yum and SL.
I switched from OpenSUSE to SL7 yesterday and while setting it up, yum could not install or update any packages. 
Whenever i try to install or update I get the following errors: https://pastebin.com/UqKyKANq 
TL;DR: I get back 404 for every repo
I tried:
Adding 3rd party repos
Changing DNS configuration
cleaning yum

This is the Link to the original forum post I created with all terminal responeses: 
https://scientificlinuxforum.org/index.php?showtopic=3740

Please ask me for whatever information you might need. 

Info:
-Operating System: Scientific Linux 7.4 (Nitrogen)
-CPE OS Name: cpe:/o:scientificlinux:scientificlinux:7.4:GA
-Kernel: Linux 3.10.0-693.el7.x86_64
-Architecture: x86-64
Everything is freshly installed.
 
I am really out of options here. It would be great if someone could help me fiigure this out.
Thank you in advance and best regards
Marius Rometsch