You need to have choco installed if you don't, run the following in a powershell with admin privileges.
Set-ExecutionPolicy Bypass -Scope Process -Force; [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072; iex ((New-Object System.Net.WebClient).DownloadString('https://chocolatey.org/install.ps1'))
choco install papercut
echo 127.0.0.1 smtp.sendgrid.net >> %WINDIR%\System32\Drivers\Etc\Hosts
If you already have choco just run the following commands in any console, with admin rights
choco install papercut
echo 127.0.0.1 smtp.sendgrid.net >> %WINDIR%\System32\Drivers\Etc\Hosts
You can continue to use smtp.sendgrid.net
in your setup. Paper cut will receive all the email regardless of the receiver. If you would like to set up another SMTP server just add it to your Hosts file or replace >HOST< in the following command line and run it with admin right.
echo 127.0.0.1 HOST >> %WINDIR%\System32\Drivers\Etc\Hosts