Да, я понимаю, спасибо за оценку, делал в последние три дня конкурса, многое не успел, многое сделал не так как хотелось бы, но не отправить уже не мог.

To interact with the server, I used a webogram, which I redone so that it would work in a webworker. I call his API calls in the controller. He returns such errors, I don’t even process them, I only deduce that there is such an error, unfortunately I did not manage to make the flow of interaction with the server myself.
But I just checked the functionality with the link, my code passed.
By the way, this hack will not work in Explorer, I did it on Linux, and forgot to check in Windows, I repent ...);