Log file fails when testing alert

I'm trying to create an alert but the log file keeps failing every time I test it. However, the e-mail does send. What would the problem be here?

Here's the error I'm getting:

"There is not file name provided for alert E:\Solarwinds-Event-Logs\POS.txt

Action type LogToFile for alert _CXL_POS failed to complete successfully."

I know the file exists and the path is correct. I browsed for it to select it.