Walgreens Couponing RR printing question

I used a Register Reward on my transaction today. It brought down the total to $2.16. I was expecting a $3 RR back for the Crest and Oral-B deal this week. It did not print. A store spend booster did print to the machine was working. Does the total you are purchasing have to be $3 or more in order for it to print? I am fairly new at couponing, so I would like to know if I made a mistake or if it was the machine. In addition, the RR was not for the same deal and it was from a different manufacturing company.

Thank you for your help