I've never used RSS feeds before in Thunderbird, but just added a couple now to test.

I can confirm that particular feed does not work in Thunderbird. When I click on the link "Check validation and retrieve a valid url", I see that the RSS feed is not valid, with details why.

This webpage shows the same thing thing you will see in Thunderbird.

It seems that Thunderbird first checks with THE authority on the format for RSS feeds first, sees that the feed is not valid, and does not try to show it.

Microsoft, on the other hand, generally disregards the rules of the rest of the world and Internet, and makes up their own rules. They want people to just use their programs, so will try to get people to use Microsoft rules so only Microsoft programs will work "properly".

My guess is that thestar.com.my has formatted their RSS feeds to work with Microsoft programs, but not to the normal rules. They may even be getting a kickback from Microsoft to do this.

@sfhowes, the website you gave is completely different, not as whatI mention above. If you did check out the website above you will know why I say so.

@Bruce A. Johnson thanks for the anser. Is there any way I can force it not to check and just stream the feeds as the site update? And what is the approach or terms I need to explain to them if I want to contact the webmaster? I believe this is not anything to do with them getting support from Microsoft, but just rather lack of skills developing their RSS.

wightfall: You can use another feed reader like sfhowes says.

If you want to try to communicate with that webmaster about fixing the feed, probably the best thing to do is to send them to this page: https://validator.w3.org/feed/check.cgi?url=http%3A%2F%2Fwww.thestar.com.my%2FRSS%2FNews%2FNation So they will see for themselves the problems. My guess is that they will not care, since the feed works in other feed readers.