Updating the Home-Assistant doc: Solving CAPTCHA issues when sending messages to new recipient via REST-API on Home Assistant

[wassong]

Hello everyone,

I ran into some issues while trying to install and use Signal on Home Assistant via the REST API. I’d like to share what went wrong and how I was able to fix it.

Problem

When trying to send a message to a new Signal account, I received the following error:

Failed to send (some) messages: <receiving number>: CAPTCHA proof required for sending to "<receiving number>", available options "PUSH_CHALLENGE, CAPTCHA" with challenge token "<challenge>", or wait "86400" seconds. To get the captcha token, go to https://signalcaptchas.org/challenge/generate.html After solving the captcha, right-click on the "Open Signal" link and copy the link. Use the following command to submit the captcha token: signal-cli submitRateLimitChallenge --challenge CHALLENGE_TOKEN --captcha CAPTCHA_TOKEN

My Steps to Resolve It

1. I registered a new landline number for use with Signal.
2. When sending a message to a number that hadn’t interacted with my instance before, I got the CAPTCHA error above.
3. I visited https://signalcaptchas.org/challenge/generate.html, solved the CAPTCHA, and copied the URL behind the "Open Signal" button.
4. I used that link in the following REST call:

curl -X POST \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
        "captcha": "signalcaptcha://<captcha>", 
        "challenge_token": "<challenge>"
      }' \
  'http://<ip>:<port>/v1/accounts/<sending number>/rate-limit-challenge'

Important Note

You will encounter this CAPTCHA challenge for each new number you send a message to for the first time. That means you have to repeat steps 3 and 4 for every new recipient.