A custom mobile Outlook add-in is not loading, which is working well in the Outlook Web

We have created a manifest file by following the link as mentioned in the Microsoft Documentation

and uploaded to O365 admin for using it in Web application and mobile application, but Add-in is not showing in the Mobile application Add-in list.

I have tried clearing cache in the mobile app and also tried PowerShell Command

Set-OrganizationConfig -OutlookMobileGCCRestrictionsEnabled $false

but it is not working.

My questions are:

Have we missed anything after deployment or in the Manifest file?
Do we need to run any other PowerShell commands to display the application in the Mobile Outlook Add-in list?
In some forums it was mentioned that the Add-in needs to be Whitelisted, is there any such thing. If so, how to do that?

Please suggest us on how to proceed and help us with this manifest file (Add-in) to be working in the Outlook mobile application.

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