Comment module on a restricted site

I would like to add the comment form on a restricted site so that users can comment on the items and add information. I want to make is as user friendly as possible: so just add a text comment, and I can use the comments to improve the data of an item. Its for a family archive site.

The comment module works. But I have some issues implementing it: only users with assigned rights as Global administrator or Supervisor are able to add a comment. But in my case the users have research rights (and for good reason). It should not be possible for users to access the admin board. Or make changes in the data in real time to prevent them for making changes in the data itself. (My dad has the ability to critically error his windows computer and not knowing what he did to cause it…)

Does anyone have a useful tip to help me get this on the right track?

Did you try to use the module Guest or Guest Private ? There may be useful for that.

I’m trying, but not really succeeding. I put the Guest module on. I set change the user to guest. I try to make a comment, I get the error:
image

Is it conflicting because I use restrictred site?