Can't complete on a computer

It says I can't complete this task on my computer, why not?

The majority of the daily tasks can be completed using your browser, however, if you see an orange exclamation point it indicates that this particular task requires the app. Some tasks which use motion sensors cannot be completed on a laptop or desktop computer. If you own an Android or iOS smartphone or tablet, you can download the app and log in the same way you do on your computer to complete those specific tasks. Otherwise, you can skip those, and your provider will take the measurements at your next in-person visit.