Action Cancelled: MSCRMKeyGenerator - 18949

When openning the CRM shortcut you promptly receive the message "Action Cancelled"

Error log details:

Source:   MSCRMKeyGenerator

Event ID: 18949

Current active key (KeyType : CrmWRPCTokenKey) is expired. This can indicate that a key is not being regenerated properly. Current Active Key : CrmKey(Id:c2e0c738-dc7a-dd11-b61e-00188b3466e9, ScaleGroupId:00000000-0000-0000-0000-000000000000, KeyType:CrmWRPCTokenKey, Expired:True.....

I recently came across this error a few times. On all occasions I had no luck in sorting it out the usual way:

Start services.msc and ensure that Microsoft CRM Asynchronous Processing Service is started.

If like in my case, you find that this service was already running, then save yourself hours of scratching and simply restart the SQL Server housing the CRM database. 

I'm yet to find the specific reason behind this error.