@Piotr-Bielecki This is a user forum we are not anyones "side".
My understanding is that with the trial version your project on the timeline needs to be no longer than two minutes. So delete anything after two minutes and you should be able to render. But your rendered video may be watermarked.
You have to understand that I tried to render my project which is 1 minute and 59 seconds long but I get a message that it has to be less than 2 minutes. Who is responsible for this? This is not fair. I can't run the Vegas trial version test!
My understanding has long been that the project in a trial version of Vegas Pro must be less than 2 minutes in length (i.e. a maximum length of 2 minutes minus 1 frame) in order for a render to occur. It is therefore recommended that the project be checked to make sure that the entire project length is in fact less than 2 minutes and that there is nothing at all on the timeline like a marker beyond the project length. It has been reported on the forum in the past that just selecting a less than 2 minutes section of a longer project in a trial version will not enable a render to occur.
A trial is meant for testing and not for producing. It's like a test drive with a car, just test driving the car and not for bringing you from point A to point B.