If you’re trying to login using Joomla login credentials, and they aren’t working, please try disabling caching in the Advanced parameters section of the SCLogin module. Also, check the Returning User Redirection setting to make sure it’s going to the right location.
Beyond that, let us know how you are trying to authenticate so we can test further. If you are using Joomla credentials, please create a test account and let us know them so we can test.
Also, can you try using the standard Joomla login module to see if that works? That will help narrow things down as well.
Thanks,
Alex