Sharing on Instagram is different than on Twitter and Facebook. First, you click on the Instagram icon, then you select “copy to Instagram” with the Instagram logo. You will then be redirected to the Instagram app as you can’t share directly from within the app due to Instagram's rules.
Make sure that you have the most recent version of Charity Miles installed and that you have downloaded the Instagram app.
If you’re still having problems, please let us know. Simply click on Contact Us in the top right-hand corner of the Help section or email: firstname.lastname@example.org.