Hi @lizbonney,
Thanks for writing in.
First, I could see that you have a lot of site. Would you mind sharing us the URL and Admin credentials so we could check further.
As of now, to fix this kind of issue.
Try other icon. Check if other icon works meaning your icon is the problem.
Check for caches that loads the old icon not the new icon. Then Clear your site cache before checking your site again.
Lastly, hosting sometimes prevents icon to be changed. Contact your hosting so that you could verify if they setup is preventing this changes.
Let us know how it goes.
Thanks.