There may be instances when you will need to get approval from the Tenant admin to add apps to the tenant's app catalog. Even if you are a tenant administrator, on occasion this message may appear.
To fix this error, you will need to request approval for the app.
Once you have requested it, you will need to go to the SharePoint admin portal, which you can find in the top right corner under admin on office 365 and then under admin centres.
Follow these steps to Approve the App
1. Click Find out why
2. Click Request Approval
3. Click Request
Go to the App Catalog to approve the request
Navigate to the SharePoint Admin Centre
1. Go to the SharePoint Admin centre using the link in the portal left-hand menu.
2. Under ADMIN click SharePoint
3. Navigate to App Catalog > From the SharePoint admin center > select apps
4. Click App Catalog
5. Approve the App Request > Click LiveTiles Design Manager (This is the request you just made)
6. Click Approve
The LiveTiles Design Manager App is now Approved!
Head to the upper right settings cog, and select Add an App to add Design to your site collection.