Can't activate website monitoring due to home_url error

I'm trying to active monitoring in my WPMU Hub and keep getting the following error:

It appears that your home_url setting is trying to redirect to another domain. This often happens when you are forcing https but haven't updated your site setting for that. Please verify that the home_url option of your WP install is correct, then click refresh updates in the Dashboard plugin.

Everything seems set up correctly on my website, and I can't find any "refresh updates" option in my website admin/WPMU dashboard. What steps can I take to resolve this?