Review the Prerequisites

Verify the following prerequisites before performing a backup and restore:

• You have the SharePoint Site Collection URL to backup.
• The backup account is a member of Site Collection Administrators groups or assigned with SharePoint admin Role.
• To add an account to Site Collection Administrators group, refer to the link.
• Install Microsoft .NET Framework (version 4.7 or higher) and PowerShell (version 5.1 or higher) on the proxy server that is a 64-bit computer.
• If Modern Authentication is set on the Office 365 tenant, install patch P00002119. For more information, see Modern Authentication.