Modbus error: Illegal data address

Problem

When using Cloud Logging or Cloud Notify with Modbus TCP, testing the variables by pressing Run test returns the error: illegal data address.

Cause

At least one of the addresses in the error message does not exist in the PLC.

Solution

Remove any variables from the CloudVPN Portal that do not exist in the PLC.

If this is already the case, try setting Read mode to Optimized in the Fleet Manager > Devices > Your device > Your data source.