Users can post to forums

I can't believe I'm asking such a basic question. I've searched the documentation with no success.

My users cannot post to any of the open categories. I can't even post as super user.

I searched under a number of different terms, but all returns about posting returned discussions about a "Rest API" - I don't know what that is.

I'm presuming it's a setting someplace, but I can't find it.

What do I have to do to set-up my site so that registered users can simply type their entry into the category?

Do I need to enter my site access information every time I submit a ticket?

I provided mine earlier; I didn't want to cause any confusion by duplicating information you already have.

Thanks

Mark