Connection failed (no connection to the remote host) WS_OPEN_ERROR_UNDERLYING_IO_OPEN_FAILED

TL;DR

Fix: If Azure speech recognition suddenly starts failing with 'Connection failed (no connection to the remote host) / WSOPENERRORUNDERLYINGIOOPENFAILED' and your code did not change, check the network path first. The reporter traced it to network proxies / regional network issues and resolved it by provisioning a new secret key in a different region (Southeast Asia).

The error

Issue Azure-Samples/cognitive-services-speech-sdk#1911 (closed, 29 comments): **Describe the bug** Using the speech recognition text function, this error will be reported starting from April 7th This is the error log [logspeech.txt](https://github.com/Azure-Samples/cognitive-services-speech-sdk/files/11188995/logspeech.txt)

Fix

1. If Azure speech recognition suddenly starts failing with 'Connection failed (no connection to the remote host) / WSOPENERRORUNDERLYINGIOOPENFAILED' and your code did not change, check the network path first.
2. The reporter traced it to network proxies / regional network issues and resolved it by provisioning a new secret key in a different region (Southeast Asia).

Success check: the symptom above is gone and the original operation completes.

When to use

• You hit this exact symptom in cognitive-services-speech-sdk.
• You want the verified fix without digging through the thread.

When not to use

• A different error in cognitive-services-speech-sdk, even a similar-looking one.
• General cognitive-services-speech-sdk setup or credential questions.

Compatibility

• Cognitive Services Speech SDK (Azure-Samples/cognitive-services-speech-sdk)

Variant phrasings

• How to fix "connection failed (no connection to the remote host) WSOPENERRORUNDERLYINGIOOPENFAILED" in cognitive-services-speech-sdk
• cognitive-services-speech-sdk: connection failed (no connection to the remote host) WSOPENERRORUNDERLYINGIOOPENFAILED
• connection problem (no connection to the remote host) WSOPENERRORUNDERLYINGIOOPENFAILED

Edge cases

• So: verify no proxy or firewall blocks the websocket endpoint, and if the region's network is at fault, create the Speech resource in another region and rotate the key.

Source

• https://github.com/Azure-Samples/cognitive-services-speech-sdk/issues/1911

In gh:Azure-Samples/cognitive-services-speech-sdk#1911, the reporter ran into: Issue Azure-Samples/cognitive-services-speech-sdk#1911 (closed, 29 comments): Describe the bug Using the speech recognition text function, this error will be reported starting from April 7th This is the error log logspeech.txt The verified answer was: If Azure speech recognition suddenly starts failing with 'Connection failed (no connection to the remote host) / WSOPENERRORUNDERLYINGIOOPENFAILED' and your code did not change, check the network path first. The reporter traced it to network proxies / regional network issues and resolved it by provisioning a new secret key in a different region (Southeast Asia). So: verify no proxy or firewall blocks the websocket endpoint, and if the region's network is at fault, create the Speech resource in another region and rotate the key. Source issue: https://github.com/Azure-Samples/cognitive-services-speech-sdk/issues/1911