This error indicates that a required lock could not be obtained. The most common causes of this are:
1. Attempting to use both direct and client/server connections to the same Atrex database.
2. Attempting to access a Atrex database using the direct connection method, but using different data paths.
One-at-a-time, start Atrex on all systems, then go to Help - System Information. Locate the "Paths" section of information and then both the "Data" and "Central" sub-sections.
Ensure that all the systems are using the same connection method and that the path listed is identical. For example, while the following paths may point to the same location, because the path specified is different between the systems, you will receive the 300 error.
A video tutorial on networking is available via the following link:
This starts with an explanation of locations and continues through both direct and client/server.
If you are not already using client/server, the following link is to a video tutorial on that subject:
Client/server provides several advantages over the direct connection method including the ability to schedule data backups.