I get the same here with this concert - URL cant be opened - will look into it later today for you.
Yes the DVR recordings are in real time and not the same quality as the stream (but pretty close).
Melonman.ru concerts however can be downloaded using Jaksta's AUTO detection mode.
1. Switch on AUTO
2. Open your browser to melonman.ru and navigate to the concert page.
3. Play the concert
4. Jaksta will detect and start downloading the concert
5. You can switch off AUTO and close the concert in your browser. Jaksta will continue to download the concert independently.
If you are still having issues then please provide debug logs as per https://www.jaksta.com/support/windows/technical/jaksta-media-recorder/how-to-generate-debug-logs-6000009063ensuring debug is on before you start AUTO mode.
Here is a picture of the concert being downloaded. Downloaded file was 1280x720 MP4.