"this webpage not available"

Hi all,
I’m trying to edit a university-based site, which I can’t do from off-campus. I can login and make the edits but, whenever I click update, I’m taken to “this webpage is not available” (Chrome). I’ve tried on Safari and get a similar error (“Safari can’t open the page). If I try to edit on campus, it’s fine. (There I use Windows desktop, here MacBook Pro.)

Wondering if it’s something about security, I’ve tried VPN, though that doesn’t help. I don’t know whether it’s something with the laptop, or else something about being on a campus network. The Mac I’m using now doesn’t have firewall turned on.

I’ve tried different browsers, tried clearing cache, and so on. I have had this problem for months.

Please advise.

Thank you,
Fritz