I see. So I am not the only one having the problem. I guess someone at Simba screwed up with the IPv6 configuration.https://simba.sg/broadband/NAS
If they do not have IPv6, then why they wrote this article ?
I do have IPv6 working for quite some time, until suddenly, it stop working totally. Called up support, and the agent mentioned they can't configure IPv6 on the ONT.
If you are on ONT, you may try to do a direct connection to your PC/Mac.