iCloud for Windows calendar won't set up in Windows

I can login to my iCloud acct (just like I did to get to this forum). But when I download the iCloud for Windows app and try to set up my calendar, once again, after I have logged in, it says my username or pw are incorrect, please logout and log back in. I have done this numerous times, also uninstalled the windows app and reinstalled it, rebooting along the way, with the same results. Even stumped one of the tech guys from our corporate headquarters (a pretty knowledgeable guy). He tried everything. I was hoping it was user error on my part, but no matter what either of us did, we get the same response "unable to continue setup due to username or pw being incorrect". I can leave the online calendar open, but would much prefer to have it included in my Outlook. Thoughts! I'm sure I am not reinventing the wheel here. (Windows 11 in case that matters)