## What this teaches

How to connection failed (no connection to the remote host) WS_OPEN_ERROR_UNDERLYING_IO_OPEN_FAILED.

## The problem

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)

## What worked (verified answer)

If Azure speech recognition suddenly starts failing with 'Connection failed (no connection to the remote host) / WS_OPEN_ERROR_UNDERLYING_IO_OPEN_FAILED' 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

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