You're redirected to your homepage when trying to view the settings page? Could you please provide an admin test account?
I snipped the login details, that's sensitive information and could easily get you hacked.
You're being redirected to a version of the URL without the "index.php" bit in it, naturally throwing a 404 error. I'm not quite sure what is causing this yet, but can you make sure you have the latest files and aren't missing any by re-uploading the whole ./admin/ directory?
Oops how stupid of me to do that,
This is what I got from looking:
index.php Changed
install/images/bullet.gif Missing
install/images/content_bg.gif Missing
install/images/error_bg.gif Missing
install/images/h2-admin.gif Missing
install/images/h2-config.gif Missing
install/images/h2-createtables.gif Missing
install/images/h2-dbconfig.gif Missing
install/images/h2-finish.gif Missing
install/images/h2-license.gif Missing
install/images/h2-requirements.gif Missing
install/images/h2-tablepopulate.gif Missing
install/images/h2-theme.gif Missing
install/images/h2-welcome.gif Missing
install/images/index.html Missing
install/images/submit_bg.gif Missing
install/images/tcat_bg.gif Missing
install/images/thead_bg.gif Missing
install/index.php Missing
install/resources/adminoptions.xml Missing
install/resources/adminviews.xml Missing
install/resources/index.html Missing
install/resources/language.lang.php Missing
install/resources/mybb_theme.xml Missing
install/resources/mysql_db_inserts.php Missing
install/resources/mysql_db_tables.php Missing
install/resources/output.php Missing
install/resources/pgsql_db_tables.php Missing
install/resources/settings.xml Missing
install/resources/sqlite_db_tables.php Missing
install/resources/tasks.xml Missing
install/resources/upgrade1.php Missing
install/resources/upgrade10.php Missing
install/resources/upgrade11.php Missing
install/resources/upgrade12.php Missing
install/resources/upgrade13.php Missing
install/resources/upgrade14.php Missing
install/resources/upgrade15.php Missing
install/resources/upgrade16.php Missing
install/resources/upgrade17.php Missing
install/resources/upgrade18.php Missing
install/resources/upgrade19.php Missing
install/resources/upgrade2.php Missing
install/resources/upgrade20.php Missing
install/resources/upgrade3.php Missing
install/resources/upgrade4.php Missing
install/resources/upgrade5.php Missing
install/resources/upgrade6.php Missing
install/resources/upgrade7.php Missing
install/resources/upgrade8.php Missing
install/resources/upgrade9.php Missing
install/resources/usergroups.xml Missing
install/stylesheet.css Missing
install/upgrade.php Missing
Let me know if I need to dig more
Those are just the install files, which you probably opted to delete instead of creating the lock file. That's fine and not the cause of the issue here.
Do you have a .htaccess file in your admin directory or something? You could have some sort of redirect going on. Also, check with your web host to see if there are any restrictions worth mentioning you should be aware of.
Yes it seem a plugin from the main site wasn't completely removed of leaving .htaccess. Got rid of it and things are back to normal.
Thank faviouz for taking the time to check the problem
.