Why does it give an error when installing mongodb?

Question

MongoDB

I do everything according to the instructions, namely
1.sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv EA312927
2.echo "deb repo.mongodb.org/apt/ubuntu xenial/mongodb -org/3.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.2.list
3.sudo apt-get update
and already there is an error in
GPG Error: repo.mongodb.org/apt/ubuntu xenial/mongodb-org /3.2 Release: The following signatures could not be verified because the public key is not available: NO_PUBKEY D68FA50FEA312927
5. when I type sudo apt install -y mongodb-org
it says "Unable to find package mongodb-org"
How to fix this?
Restart tried

Answer 1

try to execute
and then
sudo apt-get update