Server Issues and IP address

I keep getting an error message on Virgin Australia website

We’re sorry, unfortunately we experienced an error while attempting to process your request. To continue with your booking, please clear your browser cache, restart your browser and try again. If you are still experiencing issues, please contact our Guest Contact Centre to complete your booking.

I have tried Safari, Chrome, Opera and Avast browsers with no luck. I have cleared history and caches. Have turned off VPN.

i can only get into their site if I turn of wifi and use 4/5G

is this is an issue with my IP address