IPC6023 Error after changing to a new Router (DrayTek Vigor2862) - BT TV not working

[rd3]

Hi - 
I changed router to a DrayTek Vigor2862 - and now my BT Sport is not working, reporting an IPC6023 error. I've tried going through all the steps recommended (restarting router, re-booting TV Box with factory settings etc). IGMP Proxy and IGMP Snooping are all enabled. Have tried accessing the link below, but it says I do not have permissions. Can someone please help? 

https://community.bt.com/t5/YouView-Boxes/Using-a-3rd-party-router-for-Multicast/td-p/1048582

[Les-Gibson]

You'd be better off searching for IPC6023 Draytek in the search bar above