I have been trying to install an .ipa using itms-services to an iPad with iOS 9.1. However, it shows the "Install..app?" and "Unable to install.." pop-ups the same as asked in this question:
iOS 8 - Can't Install Enterprise App
The installation is successful in iPhone with iOS 9.1 (same version as iPad). I tried the installation in another iPad with iOS 8.1. I tried the suggested fixes in the accepted answer of the above mentioned question. Also, tried cleaning the Downloads folder using iExplorer. Still unable to download.
I'm able to install app using iTunes, so it's not a provisioning profile issue.
Any suggestions? Thanks in advance.