Instance Launch Credentials Not Working

I'm getting to the end of being able to actually work with my Instance that I have created. When I open my *.rdp file and use my encrypted password, generated by my RDP Client process, I get an error message when trying to Copy / Paste my password into the Windows Security pop-up window. The message says... "Your credentials did not work". I can't find any troubleshooting options or documentation. Everything looks just fine on the Instance Panel... "Running" and "2/2 Checks" passed. Any suggestions??? Newbie here... I'm new to this platform and not a computer tech guy, so any coding or stuff like that will be difficult for me to do.