Google cloud tts : error 504

Hi,
I’m trying to get TTS working through Google Cloud.
The issue is that it only works about one out of ten times.
Most of the time, I encounter the following error, even with a simple ‘hello’ TTS."

Enregistreur: homeassistant.components.google_cloud.tts
Source: components/google_cloud/tts.py:145
intégration: Google Cloud Platform (documentation, problèmes)
S'est produit pour la première fois: 08:34:10 (2 occurrences)
Dernier enregistrement: 09:35:17

Error occurred during Google Cloud TTS call: 504 Deadline Exceeded

Billing is activated, everything seems ok, and it works sometimes…

Any idea ?

Thanks a lot