U.S. Defense Secretary Pete Hegseth had an internet connection that bypassed the Pentagon’s security protocols set up in his office to use the Signal messaging app on a personal computer, two people familiar with the line told The Associated Press.

While Signal offers more protections than standard text messaging, it’s no guarantee of security. Officials also must ensure their hardware and connections are secure, said Theresa Payton, White House chief information officer under President George W. Bush and now CEO of Fortalice Solutions, a cybersecurity firm.