Nuxt app embedded authentication fails when connected connected to certain VPNs

We have an app running on a Nuxt front end and Java backend. We are using embedded login via email and password with a custom domain. Just recently we started getting reports from users that their logins are failing while on vpn. But they can login if they disconnect from VPN. (Although there is one user that claims they can’t login with or without vpn.) We’re not sure the exact response these users are getting but they report getting an error message that says {“crossDomain”:true,“method”:“POST”,“url”:“https://login.mydomain.net/co/authenticate”}. Would appreciate any help in trying to figure out what may be causing this issue.

Update: One user is reporting that Cross Origin Authentication is failing. In their network tab it reports CORS Failed for our custom domain’s authenticate method.

To anyone wondering what the issue was, it turns out our custom domain was getting flagged as malware by the user’s firewalls.