Mp4: No longer any tag changes supported

[ohrenkino]

As you can see, the OP did not answer.
What have you done in to narrow down the problem, esp. following the

Hints for asking Support Requests

If you need support using Mp3tag, you can help the community members that are about to support you in finding a solution or workaround to your problem, by following these simple guidelines. Be descriptive, also in what you’ve already tried Please give a short explanation what’s not working as expected or what you’re trying to achieve. It’s best to know any details about the problem at hand and especially, what steps you’ve already tried to solve it by yourself. Helpful information also includ…