TTS doesn't work with Nginx

[esemeniuc]

When I load a page with the TTS block, and press the play button, only the title (h2) becomes highlighted in yellow, and no sound is played. Same issue with Google or Microsoft TTS providers.

Server config:
Debian 7
Nginx 1.4.3
Php 5.4.21
MySQL 5.5.31
Moodle 2.5.1 with clean theme

Firefox Console Log:
https://gist.github.com/cwaffles/7457945