When accepting permissions in the SharePoint Admin Centre API Access page, you may see an error saying "Invalid Client ID" followed by a long string of digits.

This error is a know issue in SharePoint and Microsoft is currently working on resolving. As a work around, you can manually accept the permission request using the below PowerShell.

Note: To run the below code you need to be a SharePoint Global Admin, a Site Owner of your tenant app catalog, and have the SPO PowerShell Module installed

Connect-SPOService -Url "SHAREPOINT ADMIN URL"

Approve-SPOTenantServicePrincipalPermissionGrant -Resource "SharePoint Online Client Extensibility Web Application Principal" -Scope "user_impersonation"