How to connect Access to Sharepoint Online list

I have an Access frontend which I am trying to connect to data in a Sharepoint Online list. When I go to "External Data", "Linked Tables Manager", I select a few tables to refresh and click "Refresh". The update fails. When I try to click "Relink", I get the message, "Microsoft Access could not connect to the specified site. Please verify the address of the site or contact your site administrator." The site administrator tells me the permissions are ok. I don't know why I cannot connect to the Sharepoint Online lists. The site appears to be spelled correctly. Does anyone have a few tips to offer? Thanks in advance!