E08 errors are occasionally created by voltage surges or transient voltages. Section 3.9 of the CR23X manual explains in greater detail what a watchdog is and possible causes. If these are happening frequently, it is likely an issue with the system that needs to be resolved. The first step in this resolution process would be to check the system power (inputs and outputs) and verify it is within the expected tolerances as outlined in the Specifications page (OV-23) of the CR23X Micrologger Operator's Manual.