Issue with PnP.PowerShell Module Installation

[mjavedkhan]

Error Message:

WARNING: Unable to resolve package source 'https://www.powershellgallery.com/api/v2'.

Install-Package: No match was found for the specified search criteria and module name 'PnP.PowerShell'.

Try Get-PSRepository to see all available registered module repositories.

[mjavedkhan]

Dear Team,

I am trying to fetch all SharePoint Online site owners using PnP.PowerShell. I have registered an app and am passing the Client ID, Client Secret, and Admin URL. The connection succeeds, but I receive the following warning:

Connecting with Client Secret uses legacy authentication and provides limited functionality. Some cmdlets may not work as expected.

However, when I execute Get-PnPWeb, I encounter the following error:

Get-PnPWeb: Unexpected response from the server. The content type of the response is "". The status code is "Forbidden".

Could you please advise on what might be causing this and how I can successfully retrieve all site owners?

Thank you for your support.

Best regards,