The users may complain that while Date-Time Format on the screen is in D/M/Y YAPI sends text messages using Y/M/D format. There are  different variation of the same problem.

Important note: Canada is a mess as far as Date-Time format is concerned and allows all three formats: Y/M/D, M/D/Y, and D/M/Y. Source is here 

In Windows any user may have his own Date-Time Format controlled via Control Panel's Region app.   YAPI runs on System account that uses default  Date-Time Format which, in turn,  is configured when Windows was installed and typically being left at default value for Canada:  Y\M\D.

So if the problem is reported here is how to solve it:

1. Login to the server.

2. Open the Region and Language options from the Control Panel. 

3. Make sure that the settings listed under 'Formats' are those that you want replicated.

4. Click Administrative tab.

5. Click Copy settings.

6. Tick "Welcome screen and system account" and "New user accounts"

7. Click OK.

8. You will need to restart YAPI Service