Using Visual Studio Code and SharePoint PNP I was trying to make some updates to a list but I wasn’t able to connect to a site.

Connect-PnPOnline -Url "https://taco.sharepoint.com/" -Credentials $creds

Error I was receiving:
System.MissingMethodException: Method not found: ‘System.Runtime.Remoting.ObjectHandle System.Activator.CreateInstance(System.String, System.String)’. at SharePointPnP.PowerShell.Commands.Base.ConnectOnline.ProcessRecord() at System.Management.Automation.CommandProcessor.ProcessRecord()

I tried uninstalling VScode, removed all traces of SharePoint from my laptop, and cleared the GAC. Nothing worked.

Here is what did work:
In VScode:

1. Open the Command Palette on Windows or Linux with Ctrl+Shift+P. On macOS, use Cmd+Shift+P.
2. Search for Session.
3. Click on PowerShell: Show Session Menu.
4. Choose one of the ___ (x86) options

Not sure how, but I was using an x64 session and SharePoint PNP clearly didn’t like that.

Edit: Updated VScode to the latest version and it managed to reset my session settings. When this happened, it caused my CSOM scripts to report a The remote server returned an error: (400) Bad Request error. The fix above will resolve the error.