Thanks for your help.
I accessed the site and that very could be the reason, but I'm wondering if it's something more simple?
When I access Internet Accounts on my Mac, under a Hotmail account it asks for the password. I have tried many and to no avail. So it appears that I can't open the account or activate the account - don't know which. But I'm wondering if it's not a password problem, and what I may be able to do about that?