MongoDB GPG - Invalid Signatures

I'm installing MongoDB on an Ubuntu 14.04 machine, using the instructions at:https://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/

So I run:

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv EA312927

And then:

echo "deb http://repo.mongodb.org/apt/ubuntu trusty/mongodb-org/3.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.2.list

Followed by:

sudo apt-get update

I then get the following warning at the end of the update:

W: GPG error: http://repo.mongodb.org trusty/mongodb-org/3.2 Release: The following signatures were invalid: BADSIG D68FA50FEA312927 MongoDB 3.2 Release Signing Key

If I ignore the warning and try to run:

sudo apt-get install -y mongodb-org

I get:

WARNING: The following packages cannot be authenticated!
mongodb-org-shell mongodb-org-server mongodb-org-mongos mongodb-org-tools mongodb-org E: There are problems and -y was used without --force-yes

Any ideas on how to resolve? Thanks!