Got 502 bad gateway in batch mode with tts model

Is anyone else also using a TTS model with batch mode?

I’ve tried many times and keep getting a 502 Bad Gateway error.
I was wondering, does the current batch API not support TTS models yet?

Here is my code

client.batches.create(
        model="gemini-2.5-flash-preview-tts",
        src=[types.InlinedRequest(
        contents=[types.Content(
            role="user",
            parts=[
                types.Part.from_text(text="""
Read aloud in a warm, welcoming tone
Speaker 1: Hello! We're excited to show you our native speech capabilities
Speaker 2: Where you can direct a voice, create realistic dialog, and so much more. Edit these placeholders to get started."""),
            ],
        )],
        config=types.GenerateContentConfig(
            temperature=1,
            response_modalities=[
                "AUDIO",
            ],
            speech_config=types.SpeechConfig(
                multi_speaker_voice_config=types.MultiSpeakerVoiceConfig(
                    speaker_voice_configs=[
                        types.SpeakerVoiceConfig(
                            speaker="Speaker 1",
                            voice_config=types.VoiceConfig(
                                prebuilt_voice_config=types.PrebuiltVoiceConfig(
                                    voice_name="Zephyr"
                                )
                            ),
                        ),
                        types.SpeakerVoiceConfig(
                            speaker="Speaker 2",
                            voice_config=types.VoiceConfig(
                                prebuilt_voice_config=types.PrebuiltVoiceConfig(
                                    voice_name="Puck"
                                )
                            )
                        )
                    ]
                )
            )
        )
    )]
)

The error I got

502 Bad Gateway. {'message': '<!DOCTYPE html>\n<html lang=en>\n  <meta charset=utf-8>\n  <meta name=viewport content="initial-scale=1, minimum-scale=1, width=device-width">\n  <title>Error 502 (Server Error)!!1</title>\n  <style>\n    *{margin:0;padding:0}html,code{font:15px/22px arial,sans-serif}html{background:#fff;color:#222;padding:15px}body{margin:7% auto 0;max-width:390px;min-height:180px;padding:30px 0 15px}* > body{background:url(//www.google.com/images/errors/robot.png) 100% 5px no-repeat;padding-right:205px}p{margin:11px 0 22px;overflow:hidden}ins{color:#777;text-decoration:none}a img{border:0}@media screen and (max-width:772px){body{background:none;margin-top:0;max-width:none;padding-right:0}}#logo{background:url(//www.google.com/images/branding/googlelogo/1x/googlelogo_color_150x54dp.png) no-repeat;margin-left:-5px}@media only screen and (min-resolution:192dpi){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) no-repeat 0% 0%/100% 100%;-moz-border-image:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) 0}}@media only screen and (-webkit-min-device-pixel-ratio:2){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) no-repeat;-webkit-background-size:100% 100%}}#logo{display:inline-block;height:54px;width:150px}\n  </style>\n  <a href=//www.google.com/><span id=logo aria-label=Google></span></a>\n  <p><b>502.</b> <ins>That’s an error.</ins>\n  <p>The server encountered a temporary error and could not complete your request.<p>Please try again in 30 seconds.  <ins>That’s all we know.</ins>\n', 'status': 'Bad Gateway'}

It seems there are some updates on models page. Some models have Batch API: supported. While the tts models don’t have it. But when I tried 2.5 flash lite, which doesn’t with Batch API supported it still works well.

Also the error changed from 502 to 429 now

Hello,

Welcome to the Forum,

Batch API is recommended to be used only with the models which supports it as per Gemini API documentation.