OPMS's stuck in Checkpoint Error: 503 Service Unavailable

Products

• CA App Synthetic Monitor
• DX Application Performance Management

Issue/Introduction

Currently experiencing an issue where two out of my three OPMS servers are showing the following error. 

(-95) Checkpoint did not return status, full response: 'Checkpoint Error: 503 Service Unavailable. Sorry, cbot agent is too busy at the moment (too many checks pending)'

This issue started happening after servers were restarted during scheduled patching over the weekend. 

Environment

Release : 10.1

Component : ASM

Cause

OPMS Servers are in different versions. 

Resolution

Upgraded all OPMS to 10.4