Hi
First, your rule is disabled - have you enabled it against the correct target. You need to enable it for the same class as you used as your target. It would be helpful to see your code (export the MP and copy it here with any personal info *** out).
Have you definitely created an Alert Rule - I don't see where you have posted the Configure Alerts information. Have you accidently created an Event Collection Rule?
If you definitely have an Alert rule then also, check that you don't already have an alert "somewhere" and the suppression settings. It might be that there is an alert from days ago which you haven't spotted where the repeat count is being incremented and no new alert generated.
Another thought - keep adding lines to the file. I believe there is a water mark and it only checks new entries so if you are deleting lines then it might be that the rule isn't going back that far.
Kevin Holman walks through this here - https://kevinholman.com/2009/06/19/using-a-generic-text-log-rule-to-monitor-an-ascii-text-file-even-when-the-file-is-a-unc-path/ - double check your steps against this (although it is an old article, it is still accurate today).