Certbot Error when trying to install MQTT on CentOS 7

September 17, 2019 371 views
Miscellaneous Let's Encrypt

When following the steps here

All works up to the end of Step2. Command
sudo certbot certonly --standalone --standalone-supported-challenges http-01 -d mqtt.example.com
where I replace example.com with my domain returns

certbot: error: unrecognized arguments: -standalone-supported-challenges http-01

2 Answers


What is your certbot version? It seems like as of Certbot 0.33.0 which was released a couple of months ago and according to the official documentation, --standalone-supported-challenges had been deprecated for a long time and does the same thing as --preferred-challenges.


I’ll ask for the tutorial to be updated.

Let me know if this was the case.

Thank you for the quick answer.
I asked a friend for help since this was above my pay grade.
He used the command
certbot certonly –preferred-challenges http -d mydomain.com and it worked.
He says an update to the doc would be good.
He also says that since there was already installed a listener on port 80,
the –standalone option was not required. This could be specified in the doc also.

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