External user can not create new commercial proposal

Hi guys I’m new to Dolibarr.
I’m having a problem creating Commercial proposals from an external user of a third party. in a moment of despair I gave this external user every permission possible but no luck.
the error says ;
Access denied.
You try to access to a page, area or feature of a disabled module or without being in an authenticated session or that is not allowed to your user.
Any Idea about what should I do?