Resolving Duplicate Checkout Errors

How to resolve duplicate checkout errors

I am getting duplicate checkout errors, such as the following:

There was an issue checking out appointment 0001 for Service Call 0000634384. The technician who was trying to check out was: WESTALL

Duplicate duplicate checkout errors occur because your server is being overloaded and takes too long to pick up before TechPro "thinks" that the API call didn't pick it up so then it is sent again.