I want to add users mobile device's to their application catalog, however is empty for everyone

"A users mobile device appears in the Application Catalog automatically when it is managed by the Exchange Server connector and the Exchange Server is on-premise. When you configure the Exchange Server connector for Exchange Online, you must manually configure user device affinity for the users mobile device to appear in the Application Catalog"

Any ideas as to where to start to troubleshoot why this is not automatically working?

Have you setup the exchange connector?

Yes Exchange connector is setup, and is populating all our mobiles in the "All Mobile Devices" collection

any errors in the Easdisc.log on the site server? The primary user should be defined by the Exchange connector.

No errors in EASDisc.log everything syncs fine bar the primary user

I have manually checked the device primary users in the "all Mobile Devices" collection and can see it does infact have Username and Affinity Type = Exchange Server Connector Defined

So why would it not be populating this on the application catalog?

Root Domain = CompanyX.COM

Child Domain = HO.CompanyX.COM

Only difference I can see is the Exchange Server Connector defined username = HO\Useranme

And the users collection = CompanyXHO\Username

Will I have to get these matching in exchange?

Bump

If i manually add the user device affinity of CompanyXHO\Username it works... How can I change this to discover the correct username from the exchange connector?

Yes, I know this is an old post, but Im trying to clean them up. Did you solve this problem, if so what was the solution?

Since no one has answer this post, I recommend opening  a support case with Microsoft Customer Support Services (CSS) as they can work with you to solve this problem.