View source for Red Hat 7 registration

Reference - https://access.redhat.com/solutions/253273<br>

'''Register and automatically subscribe in one step'''<br>
Use the following command to register the system, then automatically associate any available subscription matching that system:<br>

$ subscription-manager register --username <username> --password <password> --auto-attach<br>

'''Attach a specific subscription through the Customer Portal'''<br>
After registration, you can to assign a subscription to the registered system from the Customer Portal by referring this article.<br>
After this, refresh the information on your machine using the following command. Be sure to run this any time you add or change the attached subscription from the Customer Portal:<br>

$ subscription-manager refresh<br>

'''System Administration guide''':<br>
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/chap-Subscription_and_Support-Registering_a_System_and_Managing_Subscriptions.html<br>

'''Get information''' <br>
$ subscription-manager identity

'''Removing subscription''' <br>
$ subscription-manager remove --all <br>
$ subscription-manager unregister<br>
$ subscription-manager clean<br>

'''Repos stuff''' <br>
$ subscription-manager repos --enable=rhel-7-server-optional-rpms<br>
$ yum repolist<br>

<source = "text">
It happens randomly every now and then ...
You should be able to solve it by executing :

sudo subscription-manager remove --all
sudo subscription-manager unregister
sudo subscription-manager clean

sudo subscription-manager register
sudo subscription-manager refresh
sudo subscription-manager attach --auto
</source>