Hello,
I created a HIDDEN GROUP within the forum. I have had the group for over two years. There are currently 15 members in the group. All of a sudden, some members that are ACTIVE CURRENT members are not getting access to the Hidden group, they can't even see it. I have gone to their user profiles to make sure they are members. I even tried taking them out and adding them back in as members and nothing is working.

What could the problem be?

Anyone?
I've also sent private message to support but haven't received a reply.

Have you check the permissions for that section in the administration panel?

Yes I did. I have three members so far not able to see the Hidden group. I checked permissions and it shows they are all allowed in that hidden group.

Try this for each member.

AP > General > Forum > Configuration
Scroll to the bottom of the page and resyn each member.

I did that. Also I just noticed under permissions for that group the "Allowed Access" box was unchecked. I put a check on it... but I hope that means it just makes it visible to the actual members of the group and not not everyone. It should be JUST to the members right?

Did you check here:  AP > General > Forum > Categories & Forums?  Click the permissions icon for that certain forum.  When the permissions page loads, make sure to be in advanced permissions mode.

I went to User & Groups and checked the "Allowed Access" box for the groups permissions and it works!
This matter is now solved.