iOS14.0 Unable to install app

I'm facing the same issue, but it's working fine on diawi. Someone has suggested to upgrade TLS version of the server to v1.2. I'm trying that, keep you posted if there any luck. Let me know if you find a solution. Here is the link for TLS version upgrade suggestion: https://developer.apple.com/forums/thread/652391

I finally resolved this issue. There are a couple of changes need to be aware of with iOS 14:

1. Upgrade TLS version to v1.2. You can use LetsEncrypt for testing purpose, 90 days lates version of TLS is issued for free. You can use this for production purpose as well.

2. Life time of the certificate needs to be 398 days or less.

I had the same issue. In House apps install fine from a web site link on iOS 13 devices. 'Unable to install' on iOS 14 devices.

For me it turned out to be an issue in the plist file. I had the software-package pointing to an http URL. Changing it to https resolved the issue.

I'm experiencing the same issue. I recently installed a public SSL certificate which supports TLS versions 1, 1.1, and 1.2. It only seems to affect users who have upgraded to iOS 14. My in-house app just displays waiting...

We had the same issue with iOS 14.0. We changed from http to https in the infoPlist file. It helped! It was not necessary before, and we had redirect from http to https earlier.

I'm also facing this issue. The server is already on TLS 1.2 since a few years back.
I checked that both the URL to the plist file on the download link and the URL of the software-package inside the .plist are https.
I also tried rebuilding the app using the xcode 12 to no avail.
The link still works on previous iOS versions and when I updated my iPad from 13 to 14.0.1 the installed app was still working properly, but when I deleted it I couldn't install it back.
What else could be the reason for this?

This bug has been going on for ages and I am so ‘bugged’ by it. For me, I tried to install Shortcuts. Then it says:
“Unable to install ‘Shortcuts’”
“Please try again later.”

I am facing the same issue with a watchOS only app. After upgrading to iOS 14.4 and watchOS 7.3, I am not able to install the app signed with Adhoc profiles. I am getting the "Unable to install app" .
@adrntoken, where are these .plist files that need to be https?

I resolved using IP address instead of domain name in .plist.
I don't know why resolved.
Teache me why I can resolve by this.

DNS Type 65 affects?

Still facing this issue with iOS 14.5.1. I use a self-signed cert for my apache server to build an OTA. It works just fine until my phone was upgraded to iOS 14.5.1. Nothing helped, even if I've done the following steps:

1. Checked https in manifest.plist.

2. Trusted self-signed cert in Settings -> General.

3. Upgrade Apache version, openssl version and update self-signed cert to support TLS1.3.

Any suggestion would be appreciated!

I've been using TestFlight for many years and had similar issue recently. I guess TestFlight didn't allow me to install from a certain IP address. Via VPN and from other network I could install the same build on the same device without issues.

My case: .ipa AdHoc via Firebase App Distribution, all UDID are ok, all provisioning profiles too, result: "Unable to install MYAPP Please try again". 8 hours of frustration and different attemtps... Updated Mac OS + XCode 13.3.1 to latest versions (because I had one iPhone SE that gets install without problems, iOS version 14.8.1 and supported SDK in my previous XCode version 12.2 and another iPhone XS iOS 15.3.1 with a problem). No luck. Then I read the comment above, I've already tried to perform install via VPN but via Finland servers (as I'm from Russia and that could be a problem). Finland server didn't help and I decided that this is not a problem with network. And after a whole day of fighting this problem when I was double checking and rechecking all variants I connected to the USA server (VPN) and voila(!) it worked! (The small remark: I had no problems on my first iPhone SE, successful installs all the time without VPN, same ipa, same profile) I made some other checks and I'm sure that my problem was definetely related to this. It was a hard day, really. Happy coding and hi5 dear Apple Team%)

My case: .ipa AdHoc via Firebase App Distribution, all UDID are ok, all provisioning profiles too, result: "Unable to install MYAPP Please try again". 8 hours of frustration and different attemtps... Updated Mac OS + XCode 13.3.1 to latest versions (because I had one iPhone SE that gets install without problems, iOS version 14.8.1 and supported SDK in my previous XCode version 12.2 and another iPhone XS iOS 15.3.1 with a problem). No luck. Then I read the comment above, I've already tried to perform install via VPN but via Finland servers (as I'm from Russia and that could be a problem). Finland server didn't help and I decided that this is not a problem with network. And after a whole day of fighting this problem when I was double checking and rechecking all variants I connected to the USA server (VPN) and voila(!) it worked! (The small remark: I had no problems on my first iPhone SE, successful installs all the time without VPN, same ipa, same profile) I made some other checks and I'm sure that my problem was definetely related to this. It was a hard day, really. Happy coding and hi5 dear Apple Team%)

Thank you, evsxez1, it helps people from Belarus as well.