Use itext7 with powershell

I'm trying to use itext7 with PowerShell but I'm getting error, when the dlls try to load I get the error:

"Unable to load the 'path' file or assembly or any of its dependencies. The operation is not supported. (Exception from HRESULT: 0x80131515)."

I get this error when I do :

Add-Type -Path "mypath"

Can you please help me