Error: "Cannot contact web site 'XXXX-admin.sharepoint.com' or the web site does not support SharePoint Online credentials".
You will likely see this error if you have disabled the ability for non-modern (legacy) authentication protocols within your SharePoint Online tenant.
To migrate to a SharePoint Online Tenant, you first must enable legacy authentication protocols. To do this, run the below commands against your SharePoint Online tenant:
Connect-SPOService -URL https://XXXX-admin.sharepoint.com
Set-SPOTenant -LegacyAuthProtocolsEnabled $True
- Log in to the Microsoft 365 Admin Center.
- On the left side of the portal, expand Admin Centers.
- Click SharePoint.
- Take the URL from the address bar.
Alternatively, you can go into the SharePoint Online admin center and under Access control choose Apps that don’t use modern authentication then click Allow.