IServ delivery is not saved. What to do?

I have a task on IServ that I just have to confirm. The problem does not matter how long or how often I click the save button, nothing happens and it is not saved. And that is only the case with this task. I also had a task yesterday that I just had to confirm. And there went the saving. I've already tried it with a laptop, mobile phone and tablet.

I couldn't find anything about it on the internet. Does anyone know or why?

Send it by e-mail, if it doesn't work, unfortunately you have nothing else than to leave the task and write to the teacher. Which, thank God, is very unlikely.