403 - You are not authorized to view this resource

Few months ago, we changed our hosting services. I have noticed that our menus did not work and they were showing Not Found errors for our categories, items...

I fixed this by setting Search Engine Friendly URLs in Global Configuration to "NO". Most of categories, items work just fine except few of them. Few of them show 403 error ...

If I take a closer look at the URL itself, pages with errors will have something like this:
/index.php?
option=com_k2&view=itemlist&layout=category&task=category&id=11&Itemid=125

And pages that work just fine will have the following format:
/index.php?
option=com_k2&view=itemlist&layout=category&task=&id=&Itemid=126

It seems like there is an extra "category" in the URL ...

How can I fix this?

Thank you.

UPDATE:
-downloaded website locally, and used xampp to get it up and running ... and everything works!

so it has to be my new host and its settings

the problem now is, what do i need to ask them to change? what settings?

thank you.

Hi. I really don't know. Non SEF URLs should work in any case. Check the menu links access level.