Why hasn't my deadline gone out to all users?

By default, deadlines won't be set for users who have completed training in the last 12 months.

You can amend this in the "excluded months" window when setting a deadline: 


This will tell the system to not include anyone who has complete the training that many months previous.

If you'd like to set the deadline for all users regardless of when they last completed the course, you can set the excluded months to zero and this will send to all users. 

When viewing existing deadlines, you will be able to see when the deadline was set and the exclusions that apply for that deadline: