Not every rejection is unfair. Some are just accurate.

Rejection hurts the same whether it was fair or not, which makes the two hard to separate in the first week. Some are arbitrary, some are about timing, and some are a plain reading of where you are now against what was needed. That last kind says nothing about your worth, only about this moment and this standard.

Give it a few days, then ask what was missing, and ask the person who decided if you can. Pick the one thing that would make you obviously ready next time and start on it. Some doors stay shut for reasons that have nothing to do with you.