I am having issues when trying to use my Netgear D6400 ASDL modem/router as a modem only. I have bought an Orbi RBR50 to use as a router. Is there anything else I have to do on the D6400 apart from setting the device mode to modem only, and plugging the Orbi into the D6400 internet port and setting the Orbi to login to the ISP? When I do this I cannot stream from Netflix, BBC iPlayer or Disney. Any other attempt to access the internet is extremely slow almost dialup speeds. Can anyone tell me what I am doing wrong?