It seems that PayPal prohibits the identifiers of packages that translated application names.
I had a different CFBundleDisplayName name in my Info.plist than in the translation files. Thus, the PayPal module did the same as you. After running the application once with this configuration, I could no longer run the same package identifier in my test project (containing only a sample PayPal code).
After I deleted the transfer and set the package ID to a new one, the PayPal button started working again.
I think this is a very serious problem in PayPal (for example, some may prohibit the set of ohers app identifiers, even with live apps in the App Store!). I will contact them shortly on this matter.
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