After submitting my app to the App Store for Apple to review, they emailed me back with this error. 
In xcode, I noticed that one of my plist files is missing. There isn't anything there. This is how it was exported right from Appery. Any advice on how to get this missing plist file back? 
Hello Ellen,
Could you please clarify have you changed anything on the Source tab?
If you did, these custom changes might cause the build to fail. Try to rollback the custom source changes and try to build the app again. Here is how to rollback custom source change: https://docs.appery.io/docs/appbuilde...
When you make changes in the Source view for a particular page, the visual editor for that page will not be updated (until you rollback the changes).
I didn't change anything but I deleted a file just so I could undo any source code changes that could've been made by accident. Even after doing that, I am still missing the plist file.
The build doesn't fail within Appery or even in Xcode. But Apple rejects it because it is missing that file.
If you would like to test, I have shared my app with support and it is called The Calving Book Plus. I started having this issue after I updated my libraries to 5.0. If you end up exporting to Xcode, if you do a search for the plist file, you will find that there is a place holder but it is missing the file.
Could you clarify, does it work if you export the application from the Appery.io platform directly?
I can't export the ipa because I need to make customizations in Xcode.
Is there any chance you can send me the exported Xcode file folder? I have to get an update out to fix some bugs.
This appears to be an issue with all of my apps after upgrading from 4.0 to 5.0 libraries.
Please see the screenshot below with the .plist file:
