In order to add OpenPGP public key from Public key servers. Go to Settings -> Messages -> Encryption:
- Click on Add public key.
- Click on Search in public key servers.
- Write down the email ID of your contact person and click on Search.
- Select the right public key and click on Import.
Note: Keys with no User ID (display name and/or email address) are presently not processable on our side. We plan to address this in future.