I was creating a Cloud Management Gateway for a ConfigMgr customer today and encountered this little issue. I signed into Azure but the wizard did not detect the subscription.
This was a little odd as the account I was using was a Global admin in Azure AD and Owner of the subscription. Also I’d had no problem setting up the Azure Services.
This gave me my first clue and told me that my account was only a Contributor. However I knew that the account was a member of two Azure groups. One group made me Owner on the
subscription and the other made me a Contributor. Removing myself from the
Contributor group did the trick.....