Recaptcha Key problem (omeka Classic)

We have started getting a recaptcha error reading “Error for site owner: invalid domain for site key” on our email forms in omeka classic. I’ve checked the google recaptcha settings and it does have the correct domain (digitalcollections.library.gvsu.edu), so I don’t know why it’s giving this message. Also, I’m unable to see this message on my mac-the reporter is on windows, where it apparently does show. Anyone know why I can’t see it?

Example mail form: https://digitalcollections.library.gvsu.edu/corrections/index/add/item_id/46730

I don’t see the issue either, though I’m not currently on Windows to check that. It seems unlikely to me that it’s really Windows that’s the problem… Is it possible that this user is accessing the site through a different URL, a proxy or something maybe?