I have MongoDB 3.6 installed on Ubuntu 16.04 x64. When trying to run sudo apt update, I receive the error below:

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 Release: The following signatures were invalid: KEYEXPIRED 1544811256