Thanks for the report, though it's hard to say what may be the reason.
What version of Mac OS are you running?
What browser are you using?
(Both questions might help in finding a common cause).
Have you tried another browser on the same computer?
Firefox and Chrome have a "developer console" that shows error messages. They are activated by the F12 key on Windows, though I assume it will be different on a Mac, likely in a menu structure like "Web-developer", then "Web console".
If you open that console while you have the dominion site open and hit CTRL-R, it will reload the site and any errors will be printed in the web console. If you can copy them here, that might help diagnose the issue.