TestFlight Can't add build to Internal Test group

I have already published my app to the app store. I have already a couple of versions. I created an internal test group and an external test group.

Today, I published a new version of the app to App Store Connect, which I want to add to the internal test group. But somehow, I can't select it. When I go to the Internal Test Group, there is no (+)-Sign next to Builds. When I go to the external Test group, there is. And when I select the build and click on the (+)-Sign next to Groups, I can't select the internal test group.

I checked the build version. I should have incremented it correctly. I also tried to disable the other builds, but it still didn't work.

Here are some screenshots:

Any ideas what could be wrong here?

Okay, it seems the new build is added to Internal Testing automatically, and it just takes some time. So this can be closed.