Encryption Management Server stops responding after creating a VMWare snapshot

Products

• Encryption Management Server
• Gateway Email Encryption

Issue/Introduction

After creating a snapshot of an Encryption Management Server that runs as a guest machine in a VMWare environment, it stops responding.
It is still possible to ping the server, but the services are not available.

In the vSphere interface, one can see:
An error occurred while taking a snapshot. Failed to quiesce the virtual machine.

Cause

This is a known issue affecting vSphere ESXi 5.1, 5.5, and 6.0.

Resolution

Please check the VMWare Support site for the solution: Snapshot quiescing fails on Linux virtual machines (2116120)