The survivors and widows of crewmen who died in the 2000 USS Cole attack in Yemen had filed a $315 million dollar lawsuit against the country of Sudan for providing materials for the bomb that killed 17 crew members.
The Trump administration has sided with Sudan in this lawsuit, claiming that the notification of the lawsuit was sent to the wrong address. The Administration claims that the notification should have been sent to Foreign Ministry of Sudan, instead of the Sudanese Embassy. Somebody at the Embassy signed the registered mail.
The Administration claims if the suit is allowed to proceed, then it sets a precedent that other countries can send notifications to US Embassies. It is mentioned that directives are given at US Embassies to not sign any certified mail.