Setting user to active in group not actually saving

Setting user to active in group not actually saving

Hi ... I am attempting to add and make active a user to a group. I can add their email address and then when I click the button to make them active, it says at the top that it is saved. But if I click elsewhere and then come back to the group, it shows as inactive. I tried clicking the edit pencil button and then choosing active and saving, and it says it's saving, but then when I check it again, the user shows inactive. Any ideas of what I need to do to get that working?

Thanks,
Devin.