Maxis have enable IPV6 at their exchange level which I think they not yet fully tested and already rolled up to public or live.
Therefore, most of Maxis users are facing hiccup which Maxis Technician is trying.
IPV6 still in infant stage in Malaysia and others provider still using IPV4

Get from others forum, try this:
followed this guide, then sometime on the screen it will show ipv6, untick it and the rest is similar to the guide.

https://forum.lowyat.net/topic/2535916/all

if router says auth failed just call maxis and they will fix it from their end.