Hi,
We are new to Jira Service Management and really struggling to set it up despite months of work.
We have a number of company management Spaces with which we have given different clients permission to. Raising tickets and permissions is working for everything except access to our Knowledge Base.
We have linked the Knowledge Base for each Space to our central Knowledge Base.
This is currently set up with the following permissions

The space permissions for the Knowledge Base say:

We have tried various different settings but our clients can't open the links we've added to our portal or joining emails. They see the page briefly but then get:

Despite reading lots of documentation we can't seem to get it right.
We want users to read our Knowledge Base articles from within the self service portal.
Furthermore, some links seem to open Confluence (which we don't want) and some open still within our company portal (but can't be seen). Can anyone advise the proper way to copy links?
Also, is there anyway to get Support from Jira itself? I tried the form here https://support.atlassian.com/contact#/ but it says contact your admin (which I am!)
Thanks in advance, Siobhan