Why won't Quicken 2015 start?

I purchased a new computer with Windows 10 on it. I successfully loaded Quicken 2015 from my CD and it loaded the data from a backup file. When I start Quicken 2015, it starts and then displays a login screen (I assume for registration purposes) but it won't accept my Username and Password. It says "An unknown error occured. Please try to connect later". I know my password is correct because I can log in to Quicken's website. I can't get past this screen, so Quicken doesn't open.