If your background check is stuck in “Submitted” state or has come back rejected, you can reach out to support@ncsisafe.com to inquire about the status.

This is especially important if you lived outside the United States in the last 7 years because they will require an international background check (additional cost and information). For that, they reach out by email which often gets missed and/or goes to Spam.

See here for more FAQs on background checks.
https://ussoccerfederation.my.site.com/lcsupport/s/global-search/background%20check