Rechazada por problemas técnicos

It's too yellow looking. The white balance /colour temperatue is incorrect. This needs to be corrected.

Read this about adjusting white balance:
https://www.adobe.com/creativecloud/photography/discover/white-balance.html

Underexposed. Look at the histogramm, Evrything is on the left side.

It's underexposed, and when I try to zoom in to confirm whether sharp focus has been achieved, it's very pixelated, so it appears you've uploaded a low res version here.