U.S. Selective Services has recently sent out draft letters to thousands of men that were born in the 1800s, leaving many families confused. The draft letters were sent out due to a computer error, which was brought to their attention after many family members called to report the incident.

According to Fox News, Selective Service incidentally selected over 27,000 records of men born into the 1800s and began the process of sending out letters on June 30th. The error was caught on July 3rd when concerned families of the deceased men called to report the incident. The letters threatened to confine the men to prison if they refused to register for the draft.

The error was made by a Pennsylvania Department of Transportation computer system error similar in nature to a Y2K computer error. One of the employees entering information forgot to include which century the men were born in when they were giving the records over to Selective Service. Thus the computer changed the men’s records to appear as though they had been born in the 1990s, The Guardian noted.

Selective Service had received notice of the error after 14,250 letters had been sent out and has placed an apology on its website to the families that were affected. It also ensured that the families did not need to act in regards to the letters and stated that the error has been fixed.