Im playing on an aternos server with JEI and pixelmon installed, when i throw a pokeball at a pokemon and the animation for catching starts, as soon as the ball hits the ground it breaks and i lose the pokemon forever, is there any fix to this?

Hi there, thanks for the report but this is already known. Unfortunately there's no fix at the moment but you can keep an eye on the original bug ticket for any updates here: https://pixelmonmod.com/tracker.php?p=2&t=19572

Closing as a duplicate