My friend and I just made a free trial realm together and when we tried uploading our world which we had worked on for a long time, it made it so we could not join or reset the realm. We tried using other devices and nothing worked... We kinda gave up on it but we are still looking for it to be fixed as we have 29 days left on the subscription. As far as I can see, others are having a similar issue but it was resolved by itself. That has not happened in our case, so I am writing a bug report so you can fix it before we do not have enough time on our realm to have everyone join. For the record, when we finally joined we were in a world that was reset, but we could not press any button in realm settings after we joined.