Transportation Secretary Sean Duffy took to X early Sunday to report that the primary NOTAM system was down "but there is no impact to the National Airspace System because a backup system is in place." He said all NOTAMs are available but he did not describe the cause of the outage or an estimate of when the primary system might be up again.
Even if the NOTAM system is back in service that does not mean it is useful of helpful.
Even a simple flight can generate scores, if not a hundred NOTAMS. It’s possible there is something important there that would affect flight safety but finding it is like a needle in a haystack.