How to connect to SharePoint online to run some PowerShell：
https://sharepoint.stackexchange.com/questions/55526/how-to-connect-to-sharepoint-online-to-run-some-powershell
Connect-SPOService : Current site is not a tenant administration site error in SharePoint Online Office 365 Site
https://www.enjoysharepoint.com/connect-sposervice-current-site-is-not-a-tenant-administration-site/
current site is not a tenant administration site Connect-SPOService error in SharePoint Online Office 365 Site
https://www.enjoysharepoint.com/current-site-is-not-a-tenant-administration-site-connect-sposervice-error-in-sharepoint-online-office-365-site/
Connect-SPOService : The remote server returned an error: (401) Unauthorized.
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_o365admin-mso_manage/connect-sposervice-webexception-401-unauthorized/c3b68bf3-2c3f-44b6-8072-b0e0bd9c699d