TestFlight - No users in build permission list

I'm trying to deploy my app for testing via TestFlight. I've invited 2 other people to the team I've created and added them to a distribution list, yet the app does not show up for downloading to them, it does for me.

When I go to the build permission screen on the site this is what I see:

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Only I show up on the permission list even though there are 3 people in both of the distribution lists. Any idea what's happening here?

EDIT: this is what is seen in the people tab:

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Solution

Have you added their UDID's to the provisioning profile, rebuilt the app, and uploaded a version that includes their UDIDs? From the TestFlight FAQ:

For a Developer Sign up with TestFlight and create your team. Invite and gather the UDIDs from the team members and add them to your Apple Developer Portal and provisioning profile for the app. Build the IPhone Application (.IPA) and upload to TestFlight. Distribute the build to team members and let the magic happen. Receive feedback, monitor tester's activity and perform a full fledge beta test from the comfort of your chair. Developers on teams can also upload multiple apps for testing/internal distribution.

Here's a definitive way to verify that their UDID is in the IPA:

unzip the .ipa
look at Payload/appname/embedded.mobileprovision
look in the "ProvisionedDevices" array

If their UDID is not there, you need to check your provisioning profile and rebuild your app/ipa. TestFlight looks in the IPA to determine who is provisioned for any particular build.