Can't Access Feed Page

Hi, I’m still a newbie to WordPress. I just built a blog and build my own custom theme. Things went well, until I found that I can’t access my feed url.

Here is my blog, https://webdesigninspirationtoday.com. While I use permalink, the feed page should be able to be accessed in https://webdesigninspirationtoday.com/feed

However, every time I hit that link on the address bar. It won’t response.

Anyone has the same problem? Or know what caused this? I suspect this is one of my plugin doing.