I think Furry, as usual, is right on the money. I have observed on my A series 655, that if your router is set-up correctly, and if you don't have (INFO) entries checked, virtually nothing will be on your log and therefore nothing will be mailed.
As a diagnostic tool, check all the log alert types, including INFO, put in your e-mail information properly, choose a schedule and see what happens. Make sure you "save" your settings into non-volitile memory. That will be confirmed on your log as your first INFO alert.
Eventually you will tire of INFO alerts and uncheck it. At that point you can continue a schedule of empty, or nearly empty logs, or just assign it to be sent when full, which could be never, if you have excluded INFO alerts.