Our free accounts do have some limits, including storage. You're seeing the error message "Disk full" because some of our free hosting servers have been struggling with disk space recently, however, we can assure you that we're constantly cleaning it up!
The procedure is manual, which takes a lot of time and we bet you can imagine how many users we have over on our free services.
If you'd like to unleash your full potential and bypass any resource restrictions, we highly recommend checking out our paid packages, where you don't have to deal with any of this! You can find them at hostinger.com/go-online
If you're still not ready or simply need a testing ground for your site, we offer checking out our refreshed free hosting project over on 000webhost.com, which currently has all of the resource limitations on point.