InDesign export PDF tagged issue

Hello,

I do not know if some of you can help me, I have some technical problem with an InDesign file. This is a file that I have taken from someone else and it seems that even if the Tagged PDF option is checked, the paragraph styles are applied, the exported PDF will nerver include tags. There is probably an option that has been changed previously by someone else and I do not know how to change it.

Hope someone can help me.

Regards