# Unable to establish connection to MQTT broker on AWS IoT Core

**URL:** <https://forum.sierrawireless.com/t/unable-to-establish-connection-to-mqtt-broker-on-aws-iot-core/27938>\
**Category:** HL78\
**Created:** [September 20, 2022, 3:28pm UTC](https://forum.sierrawireless.com/t/unable-to-establish-connection-to-mqtt-broker-on-aws-iot-core/27938 "2022-09-20T15:28:48Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\
**Post date:** [October 3, 2022, 8:05am UTC](https://forum.sierrawireless.com/t/unable-to-establish-connection-to-mqtt-broker-on-aws-iot-core/27938/2 "2022-10-03T08:05:33Z")

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You can download stunnel and run in client mode to test your cert and key with mutual authentication.  
This can isolate if there is cert problem

Other user found it is working fine:

> [@HL7800-M SSL connection error](https://forum.sierrawireless.com/t/hl7800-m-ssl-connection-error/22893/4):
>
> When will FW 4.6.6.0 be released for us that don’t use FOTA?

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