I am trying to make an ad hoc build, but I get this "the signer is not valid" error when people try to sync my app to their ipad. I'm getting confused because I look around and there is mention of this "Entitlements.plist" file that is not mentioned at all on this page in the provisioning portal:
https://developer.apple.com/ios/manage/distribution/distribution.action
Do I have the wrong how-to page? I followed that page correctly, I thought, but am having a hard time testing what exactly is wrong because on my ipads I get this team provisioning profile which seems to make everything work ok (I can't get the error). Could the problem be that in my Target's GetInfo I had the Code Signing Identity's "Any iOS Device" field set to iPhone Developer and not to the Ad Hoc Provision item?
Or do I need this entitlements plist file that isn't mentioned in the link above?
Yes, your assumption is correct regarding the code signing identity.
The team provisioning profile makes everything work only on the development devices. Ad-Hoc builds require an Ad-Hoc distribution profile instead for signing.
Make sure in the configuration for creating ad-hoc builds to choose the "iPhone distribution" certificate for "Code Signing Identity" instead of the "iPhone developer" certificate.