If you see a notification saying ”You are only able to invite others who do not belong to another institution,” it means that some of the team members you’re trying to invite are already part of another subscription.
To resolve this, those team members should contact their current admin and ask to be removed from the other subscription. Their admin contact information is available on the Subscription page.
Once your team members are removed from the other subscription, please try inviting them again.
If you’re inviting multiple team members and unsure which of them belong to another subscription, try inviting them one by one.