How to increase TTS request limits?

By default, The real time synthesis API limits requests 200 per second. This is enough for almost all customers.

When TTS service responses code 429, the most likely reason is that service doesn't have capacity to handle current requests. It will scale up soon and this issue will be recovered. Increase TPS limit doesn't help. This is the best practices to resolve 429 error.

When your requests over the limit, it will be throttled. Please check your current TPS. If it's really close to the limit, you can open an Azure support ticket to increase the limit.