Catalyst - The app name you entered is already being used for another app in your account.

I just ran into this, too. Any luck on your end? Did you contact App Store Support? Hopefully this is just a temporary glitch as Apple rolls out the Universal Purchase functionality, and not a new requirement to bundle the apps as a universal purchase.

I contacted Apple Developer Support, and the representative actually told me to put a space at the end of the name of the Mac app to make it slightly different from the iOS app. Surely that's not an official solution. I've replied three times to clarify whether this is an intentional change on Apple's part, or a temporary bug in App Store Connect, but he won't answer directly. He says the names must be different, which implies this is a new policy, but he won't acknowledge that this was supported two weeks ago or explain why it changed.

FWIW, I released my Mac app with an X at the end, like "App Name X." It's meaningless, but at least it looks intentional, rather than putting a space at the end, which would just look sloppy.

I tried one more time and got an acknowledgement that Apple has changed their policy regarding app names. I wonder if at some point this will affect the apps I've already released, or if Apple will ever force developers to offer Mac and iOS apps with Universal Purchase.

It's obvious they made it intentional. Now that all iOS support MacOS, they want us to remove our Catalyst Apps and with it.. make a bloody mess with our client subscribers which will ask for a refund or form of transfer and that won't be possible.

Its a fuking mess. They should never have release Catalyst in the first place, cause now, we can't support anymore languages and that is fuked up.