Having trouble with RSS

I have two blogs. The rss of one of them appears on the wordpress.com reader but the other one does not appear.

What could be wrong? Could it be the theme? Do I have to activate the rss? because I don′t remember activating it with the other blog.

The blog that I′m having the trouble with is https://thirtysomethingchic.com/

Thank you for your help.