If you are using a school-issued computer, you may be blocked by a security setting imposed by the school.
Here are some things I would try:
- Several students and teachers have reported that blocking cookies in their browser was responsible for not being able to access Submit. Open Settings and click on Advanced. Click on Site Settings under the Privacy and security heading. Do you see Blocked under Cookies and site data? Open it. Enable cookies here to make sure Google Drive can use them to create a subfolder for the new Submit assignment to store videos in your account. It should now read Allow sites to save and read cookie data (recommended).
- Are you using more than one Google account in your browser? This might limit your ability to create a subfolder for Screencastify Submit. Sign out from all but one account in which your Submit folders should be created. To do this, open a new tab, click on your profile pic and select the Sign out option.
- Clear browser and app cache and cookies. Open Settings and click on Advanced and select Clear browsing data. Under the Advanced tab, select Cookies and other site data as well as Cached images and files options. Click Clear data. You may have to sign back into Google Drive after doing this.
If none of those options work, I would reach out to your Google Admin team and ask them to whitelist Screencastify so that you are able to use it.