Hi WebRunnerDesigns and Melanie D. -
We've seen this issue before where some networks incorrectly restrict access. This can happen for some companies or organisations such as libraries, or Universities. It can also happen if you're using a VPN which doesn't allow certain long running network calls.
I'd recommend trying it out on a different network and reaching out to your network administrator to see if they can help. Unfortunately if it's what I think it is there's nothing we can do on our end.
Alternatively, one of our Lumers also encountered a login issue while using NordVPN. Interestingly, even though they weren't actively connected to the VPN itself, NordVPN's built-in "Threat Protection" feature (which acts like an additional firewall) was enabled by default and seemed to be interfering with the login process. Within Threat Protection, there's a "Web Protection" setting. By disabling this setting it has helped them with the login.
Please let us know if any of that works for you both!