Installed Tumbleweed a week ago on new laptop. Today, tried to install on old laptop which will go to a good home. It can’t add the OSS repo, but the newer laptop (installed last week) has no problem reaching it, to download a package or even to add a second instance of the repo. I tried selecting by URL instead of from the community list, but no luck. Is the problem with the repo or with me?
There seems to be a problem with Tumbleweed repos at present.
Here’s another thread on the issue.
https://forums.opensuse.org/showthread.php/530986-6-May-2018-No-update-possible
Maybe wait until tomorrow, and see if it is fixed.