There have been random reports of people using Firefox on Windows to try to sign in to ArtStation. When signing in, it redirects to the home page and it doesn't look signed in at all. This only affects Firefox on Windows (not Mac). Other browsers such as Chrome appear to work.
We found that there is an issue specifically with Firefox when the user's clock is not set at the right time. Check your system clock and ensure that it is synchronized to the correct time.
Please ensure that Firefox allows cookies to be saved. We've noticed that in some cases, privacy settings have been set so that no cookies are saved.
In your Firefox preferences, set History so that Firefox will Remember history:
This one is drastic - remove all history on the browser. This will remove all cookies and cached pages, allowing your browser to be starting from a clean slate.
If the above don't work, please contact us at email@example.com.