pgAdmin 4 / PostgreSQL 10 Won't Open

My name is Joseph. I am a university student that is using Lynda.com to learn how to use PostgreSQL. So I have installed PostgreSQL 10 and it came along with pgAdmin 4. Upon doing so, a dialog box comes up with the message “Fatal Error: The application server could not be contacted.” I have installed pgAdmin and PostgreSQL under their default settings, and set it on Port 5432 without any other changes or scripts included. Is there a way for me to fix this issue? If you need me to provide any details, let me know.