Links in posts not visible on homepage (index.php)

Hello There!

I’m starting a new blog but I ran into a small problem. My links in a post (also bold text, underlined and other formatted text) is not showing up on the homepage (index.php). Actually the text is showing but not as a link or bold text but just plain normal text.

If you click on the post title and watch the single post, everything shows up normal as it should and works fine.

Somebody had this problem already and can help me out?
Hope I explained good.

Thanks a lot