I'm trying to set up as a repeater on a Royal Caribbean ship and am getting the following page pop up instead of RCLs login page:
Webpage not available
The webpage at https://onboardicafe.com/royal/disconnected.aspx could not be loaded because:
net::ERR_NAME_NOT_RESOLVED
Does anyone know how to resolve this?
It sound like a dns issue.
Please use the default dns or gateway ip it shows in your home screen of the router, to make a test 
, also i forgot: disable dns rebind protection too if that was enabled inside the routers dns settings.
if this is the case that it resolves with their dns, then yes on longer term it is also possible to use different dns with some more advanced changes.
What is your router and firmware?
Pls upgrade to 4.6.x which optimized the portal detection.
If you are using older firmware, pls do: