I\'m using command line xcodebuild tool to export ad-hoc distribution ipa file out of my archive like this:
xcodebuild -exportArchive -archivePath /path/Arch
I had the same issue since two days, The issue came from Apple certificates. Delete Apple Worldwide Developer Relations certification Authority from your keychain (would be expired at 14 Feb) and so renew it by download :
https://developer.apple.com/news/?id=02092016a