tengo el archivo que busca la aplicación en la memoria interna del celular.
It would really help if you provided a screenshot of your relevant blocks, so we can see what you are trying to do, and where the problem may be.
To get an image of your blocks, right click in the Blocks Editor and select "Download Blocks as Image". You might want to use an image editor to crop etc. if required. Then post it here in the community.
Where does this file (clave.txt) come from and where is it located?
almacenamiento interno del celular
my guess is, you are trying to read a non media file, which has not been created by your app, which means, you will have to use SAF to read it