I have a _VERY_ Basic Question About the “Reminder” Feature

Hello Everyone!

I only Recently discovered “Microsoft To Do” {_For Windows_} & have found it to be EXCELLENT as my To-Do Program --- BUT!!! There is one KEY Feature that I have NOT been able to Figure Out . . .

I Really, Really Need the ""Reminder"" Feature—because I will have (for example) a meeting coming up at 3:00 PM, and I will be working away — Confident that my To-Do Program Surely wouldn’t let me forget about my (important) meeting . . . 

Only it has not worked that way!!!  INSTEAD, I ::

• 1.  Click on that Meeting To-Do Item;  THEN
• 2.  Click on “Remind Me”;  THEN
• 3.  Click on “Pick a date & time”;  And Finally –
• 4.  In the Date/Time Drop-Down, I SELECT::  “TODAY At 2:50 PM” . . .

And Then I Return to Work, Knowing that my Trusty To-Do Program will Notify me precisely at 2:50 PM – –

BUT!!! That did NOT happen—IN FACT—Precisely NOTHING Happened::  I TOTALLY missed my Meeting!!  

Since that unfortunate incident, I have tested the (Supposed) “Reminder” Feature in EVERY Conceivable way, and I have NEVER got it to produce Even ONE Single Reminder!!
. . .  SOooo I’ve been using an external DUMB Sticky-Note app that reminds me PERFECTLY—To the SECOND!!

Can ANYBODY please suggest a Possible Reason that the Supposed Reminder Feature does __Absolutely NOTHING__ ?!

Thank You Very Much For Your Help! !!

– Chuck