Issues found in the nominated system while creating cache repository

You can see the error messages if:

The following are the reasons:

No active/working internet connection without any firewall restrictions makes it difficult for the Nominated System(NS) to reach the RH portal.
The Nominated System must have a Patch Manager Plus agent installed.
A certificate key named 'sslclientcert' is used to establish communication with the RH portal. When this key is invalid/missing in the Nominated System, you will not be able to download/upload files.
The Nominated System might have a transparent proxy that tampers with TLS security.
The Nominated System might have an incorrect system clock.

Ensure that the nominated Red Hat machine has a Standard Red Hat Enterprise Linux subscription that points to Red Hat's CDN.
Make sure your internet connection is working.
Install agents in the Red Hat machines that are to be managed using Patch Manager Plus .
How to resolve when the sslclientcert certificate key is missing/invalid?
Detach/remove the subscription from the system. Then, again attach the subscription to the Nominated System (NS). This resolution should help in providing the "sslclientcert" key.
Configure proxy in YUM (Yellow dog Updater Modified) and ensure that there are no other proxy settings that tamper with the TLS security configurations.
Ensure that the Nominated System's time is correct and up-to-date.

In case you are not able to troubleshoot the error, and the problem still persists, then contact support team with the Log files.