The app name you entered is already being used.
On the App Store app name are unique.
Change your app name from the WordPress plugin and request an update.
Full error log:
The app name you entered is already being used. If you have trademark rights to this name and would like it released for your use, submit a claim. The app name you entered is already being used. If you have trademark rights to this name and would like it released for your use, submit a claim.