Google TTS not generating wav files

Running Freepbx 6.12
I recently installed google TTS by following the steps on github but for some reasons it is not creating wav files on /var/lib/asterisk/sounds/tts just *.txt. I added the proper permissions to /var/lib/asterisk/agi-bin/googletts.agi and /usr/bin/googleTTS/googletts-cli.pl, I also modify the /var/lib/asterisk/agi-bin/propolys-tts.agi to include on engine on the code:

case 'googleTTS':
exec($enginebin." -l en -f $textfile -r 8000 -o $wavefile");
break;

Am I missing something?

Thanks in advance