You don’t have the proper credentials to access this page when trying to insert a guest entry i get the following response from craft:
You don’t have the proper credentials to access this page.

What can i do to avoid this and still insert the entry to craft? It needs to be an anonymous user.

Thanks in advance,
Be sure that you're testing as a logged-out user on the front-end of the site.  If you have an active Craft session, you could be getting a false positive error message.