503 Service Unavailable on /synthesize TTS endpoint (Unity Voice SDK)

[VictorChenCA]

Just like #2824 , I'm also experiencing 503 errors on the /synthesize TTS endpoint since 1/12.

Environment

• Platform: Unity 2021.x / Meta Quest
• SDK: Meta Voice SDK (Wit.ai integration)
• Voice: REBECCA

Error Details

HTTP/1.1 503 Service Unavailable

Full error log:
[VSDK TTSSpeaker] Load Failed
Error: HTTP/1.1 503 Service Unavailable
Voice: REBECCA
Cache: Persistent
Text: Hello this is a sample text.
Elapsed: 2742.3ms

Behavior

• Same app and configuration worked previously (been running a study for 3 weeks)
• Both disk cache download and streaming fallback fail with 503
• Error is persistent over all non-cached files and through multiple retry attempts
• Affects production Quest builds

Impact

TTS narration fails completely, blocking user experience.

[provuthy9988-eng]

003857154