Activating Sintel Forms on newly created tenants

For SharePoint tenants created after August 2020 it may be necessary to perform one extra activation step in order to use Sintel Forms. If that is the case, you will receive the following screen:

As described in this thread on Microsoft’s Q&A section, a SharePoint administrator needs to perform the following steps:

1. Make sure that SharePoint Management Shell is installed
2. If it’s installed, make sure that it is up-to-date (using the Update-module cmdlet)
3. Connect to the tenant using the Connect-SPOService cmdlet
4. Execute the following code: Set-SPOTenant -DisableCustomAppAuthentication $false
5. Wait a few minutes for the changes to be applied to the tenant