Firstly, you’ve only been on here a week so give it time.
Specifically, this part of your gig description: “I have a degree in Engineering in Electronics so you can be sure that I’m a professional and I’m familiar with the vocabulary in this area” makes it sound like you want to translate in this area and so some possible buyers might be turned off by that.
Also, despite the fact your English is very good, it is not perfect, and English native speakers wanting a translation from Spanish probably want it to sound as if it’s been written by an English speaker.
If I were you, I’d look for gigs you can do that use your degree and are more technical. You may even want to set up a gig that says you’ll specifically translate technical articles in your technical area.