Troubleshoot: OpenHAB update problem

I’v got openHAB installed under raspbian on Raspberry Pi 2.

And have a problem with “apt-get update” command. I’m getting this error:
W: GPG error: stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 075721F6A224060A

My /etc/apt/sources.list.d/openhab.list contains this:
deb stable main

Is everything okay with public key?

Did you follow the instructions here to import the repository keys? I know a couple months back they had to update the keys so maybe you need to do it again if you did it before.

Thanks a lot Rich! It helped.