Are you Hosted or On-Prem customer? If you are hosted, I can look take a look at permissions and settings.
If you are on Premise you can check the admin console to see if there are any redirects in place that are redirecting you to a different page. (Admin Console > System > Settings > Redirects)
Check the permission Level of your user to ensure you should have access.
Check the status of the space by running the following against your database. The status of a published space should be 1
SELECT * FROM jivecommunity where displayname ilike '%insert-display-name-here%';
To identify your display name look at the URL you are trying to access and find the name after /community/
Let me know your user should have access to the space and if there are any redirects.