Possible error encoding bibliography in Biblatex

Question

I am writing my thesis with LyX and managing my references with Zotero. My document class is Book (Standard Class) and the style format is Biblatex. I am having a problem with my biblatex bibliography. From Zotero, I export the bibliography in Biblatex (UTF-8) into a .bib file.

This is part of my .bib file:

If I insert a citation, for example, "Martín Martínez 2013" what I get is all the accents wrong:

But, I discovered that if I open the .bib file with Bibdesk, and modify anything, it re-encodes (I suppose) the file, and then from LyX I do get the right citation. This is my -bib file after editing with Bibdesk:

Seems to me an encoding problem. I have followed this topic Biblatex encoding, but is still not working. Any ideas? I can survive with this rudimentary method but I would like to solve it. Thanks.

Update 1: When I try to compile the LyX file without having edited the .bib, I get an error. This is the LaTeX log:

Package biblatex Warning: The following entry could not be found
(biblatex)                in the database:
(biblatex)                touring_club_italiano_napoli_1931
(biblatex)                Please verify the spelling and rerun
(biblatex)                LaTeX afterwards.

And in the Biber log:

[640] Utils.pm:395> WARN - I didn't find a database entry for 'touring_club_italiano_napoli_1931' (section 0)

Update 2: I am adding a minimal example and the .bib file. When exporting my file to LaTeX (plain) I have had two warnings:

1. Said something about blank spaces in my Bibtex route. It will be unable to find the bibtex biliography. I did not copied the text and now I am unable to reproduce this warning. Is strange because I am not using Bibtex...
2. Something about the figures

And If I try to open the .tex file with TeXShop I have also another warning:

1. This file will open with encoded characters in IsoLatin9. Unable to open the file with Unicode (UTF-8) encoding because the file was not saved with this encoding. (Translation is mine from Spanish)

Minimal example:

%% LyX 2.3.6.2 created this file.  For more info, see http://www.lyx.org/.
%% Do not edit unless you really know what you are doing.
\documentclass[12pt,oneside,spanish]{book}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}
\usepackage{graphicx}
\usepackage{setspace}
\onehalfspacing
\usepackage{babel}
\addto\shorthandsspanish{\spanishdeactivate{~<>}}
\usepackage[style=authoryear]{biblatex}
\addbibresource{\string"Texto/Capítulo 2/CAPITULO II.bib\string"}
\begin{document}
 \parencite[104]{hernandez_redondo_diego_2000}
\printbibliography
\end{document}

And this is my .bib file from Zotero:

@article{hernandez_redondo_diego_2000,
    title = {Diego de Siloe, aprendiz destacado en el taller de Felipe Bigarny},
    abstract = {El hallazgo de un documento conservado en el Archivo de la Real Chancillería de Valladolid, permite constatar la presencia del joven Diego de Siloe en el taller de Felipe de Bigarny en los años precedentes a su viaje a Italia, donde trabajó con Bartolomé Ordóñez. La reclamación de Diego de Siloe de una cantidad que le adeudaba Felipe de Bigarny, dio lugar a un pleito cuyas sucesivas sentencias confirman la participación de Siloe en los trabajos de la sillería de la catedral de Burgos, al tiempo que permiten deducir algunos datos inéditos en la biografía de ambos artistas.},
    pages = {101--116},
    number = {5},
    journaltitle = {Locus Amoenus},
    author = {Hernández Redondo, José Ignacio},
    date = {2000},
    langid = {spanish},
    file = {Redondo - Diego de Siloe, aprendiz destacado en el taller de.pdf:/Users/eacosta/Zotero/storage/PF7HNQBC/Redondo - Diego de Siloe, aprendiz destacado en el taller de.pdf:application/pdf},
}