I followed the step-by-step instructions but when I got to the point where I hit "Next" after selecting a destination ("Contacts"), I received an error message. Help!
Are you still in the old email format or the new one? To tell, look at the URL in the address bar. If it says Zimbra you are in the old one, if it says Appsuite you are in the new one. If in the new one, you can't export right now as that function is offline again. If you are in the old one, the address book is provided by Plaxo. You can try to sign directly into your account with them using your Comcast credentials here-----------------
Open the Address Book there, and you will see the Export button in the toolbar. Try the export from there. BUT DO IT NOW. The Plaxo website might not work after midnight tonight. They claim they are discontinuing the service as of 12/31/2017. You can also get instructions here----------------