Hi Jorge Ramos,
You have to make sure you're using the correct translated caption in the target tag just below the source tag.

Here I'm translating to german.


The default language is English which is the language of the Base Application.. when you add the translated file to the project the source and target language are the same as the default language.
You can translate to any language only from the default source language in your translation file.
Also, see the language code for both the source and target.
Just add the translated version, to see the translated version change the language.
Regards.