If you don't have any manual DNS configured, it looks like the DNS used by your carrier may be broken or blocking that address.
When you use Wifi, it is using the DNS provided by the Wifi router/network. When you use cellular, you are using the DNS provided by your carrier.
Can I configure a manual DNS to work on the mobile network or is it just the carrier DNS used? if so I'm guessing this is a carrier tech call not a device tech call?