You may be flagged because you are required to appear as a witness in a case and haven't responded to previous summons.
National alerts for individuals with pending court cases, unpaid fines that have turned into warrants, or "interdictions" (travel bans).
You can check if you have outstanding fines or legal issues through the Ghișeul.ro portal or by visiting your local police station's "Cazier Judiciar" (Criminal Record) office.