Usability pdf : table of content page with tabulation issue

Hello

I have create a automatic table of content in my document.

After the exportation in pdf I try to navigate with the tab key. Jaws is active.

The problem is that the focus can't go further that the table of content page.

It makes a loop into this page.

If I click on the page 5 and that after I tab : the focus go back into the table of content.

Why? Someone can help me please? 
Thank you
Isabelle