member profile not visible

I’m developping a site that is not online yet, but here is the question:

* I have written a comment on an article as an admin, and I have written a second comment using another account as a member

* when I’m logged in as admin, I can click on my own name or the name of the other account, and this will open the page with my profile, or the profile of the member account for the second comment

* when I’m logged in as a member, when clicking either on the admin name or the member name in the comment, I’m redirect to the homepage of my site, and not to the profile page.

I’ve tried all the settings, that is: both the generel UM settings and the UM user role settings, but that seems to make no difference. I also tried to change the WordPress role for the UM-member account. I made sure clearing the cache, but that didn’t help either.

I can’t figure out any more where to look for the solution, so I hope someone can help me out.