Hi @Sean-McK,
You can check Adobe Repository availability status under https://status.adobe.com
I am assuming you are getting the error trying to access repository directly from browser? If so, this is expected according to Adobe Documentation:
Note: repo.adobe.com is currently not configured to be browsable with a normal browser, but maven use only.
Under above link you will also find details how to configure your settings.xml correctly.
As far as I know, most of the artifacts provided by Adobe can also be found under Maven Central Repository.