After upgrading to iOS 7.1, a website that was previously deployed using OTA encountered the following error when installing the app:
Cannot install applications because the certificate for www.example.com is not valid
This issue did not exist in version 7.0 and earlier. After investigation, it was found that starting from iOS 7.1, it is mandatory to use the https secure connection method for successful deployment. The URI of the plist file and ipa file for OTA deployment must start with https, whereas http was sufficient before 7.1. This affects the Ad-Hoc and InHouse deployment methods used for internal enterprise deployment.
Below are several solutions found on Stack Overflow. If you do not have an https server at the moment, deploying via Dropbox is also a good option http://stackoverflow.com/questions/20276907/enterprise-app-deployment-doesnt-work-on-ios-7-1?utm_campaign=ios_wiki_com_issue_4&utm_source=ios_wiki_com&utm_medium=website
Additionally, starting from iOS 9.0, the use of Https as the transmission method for the http protocol is mandatory. This applies not only to OTA deployment but also to the content of the app itself. lidaren.com has already fully adopted the https protocol to provide support. If anyone needs it, I can offer free OTA deployment services here, but the quantity is limited. Please leave a comment in this article to request it.