Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
What are they experiencing when you state, they couldn't access the poll? Is the end user given a "circling" animation that just leads to nowhere or are they redirected back to their Inbox. Also, are they using OWA or Desktop Outlook?
Not sure if clearing browser cache or verifying it in incognito helps, but it's worth a shot.
-M