If you're reading this, it most likely means you tried to push to a legacy WoW CurseForge or WowAce repository. Those have now been migrated to the new CurseForge stack, and you will need to clone the new repository, or update the origin.
The new stack runs entirely over HTTPS, and it uses your standard Curse username and password. In other words, you can no longer use SSH, or the legacy stack's generated passwords for SVN.
Finding your new repository URL
Finding the new repository is easy! Simply go to the Source tab on the project, and all details will be there. You will not be prompted for username or password until you push or commit.
Any existing mainline repository has been set as the active repository for their respective projects, and non-mainline repositories have been archived.
Accessing archived repositories
To access an archived repository, you must set it as the active repository. This will archive the currently active repository and make the archived one the active repository. You can do this in the source tab under settings.
Configuring the new Packager
With the new CurseForge stack also comes a shiny new Packager. You can configure its behavior in the source tab under settings.