For those who live in Singapore and are on StarHub, you might be affected by the network.
It seems like StarHub network is down and users are suggesting that changing the DNS address might solve the issue and it seems like the case.
After changing the DNS address, it seems like I’m able to access the Internet once again.
Currently I’m using Google Public DNS and so I’ll give you a link on how to change to Google Public DNS by yourself. If you want to use other DNS address, you will have to look it up by yourself.
Google Public DNS address are: 18.104.22.168 and 22.214.171.124.
Follow these steps which are provided by Google to change your DNS address to Google Public DNS.
LINK: Google Public DNS
For more information: LINK