Moodle missing_registration_token error

Hi,

I am trying to connect Moodle with a Laravel tool using Celtic LTI. I managed to debug most of the issues, but now I am stuck again.

When I register the tool manually, I have no way to set the Consumer Key in Moodle. Sadly, this key is required as I am sending back scores from my website to Moodle.

I thought that maybe using the Add LTI Advantage button instead would solve this issue.

This however does not work. I pinpointed the issue to a call the following endpoint:

https://[otherdomain].com/mod/lti/openid-registration.php

ceLTIc\LTI\Http\HttpMessage {#2655 ▼ // vendor/celtic/lti/src/Tool.php:950
  +ok: false
  +request: "{"application_type":"web","client_name":"Unnamed tool","response_types":["id_token"],"grant_types":["implicit","client_credentials"],
"initiate_login_uri":"https:\/\/[domain].vip\/lti","redirect_uris":["https:\/\/[domain].vip\/lti"],
"jwks_uri":"https:\/\/[domain].vip\/jwks","token_endpoint_auth_method":"private_key_jwt",
"https:\/\/purl.imsglobal.org\/spec\/lti-tool-configuration":{"domain":"debug.onebonsai-dev.vip",
"target_link_uri":"https:\/\/[domain].vip\/lti","custom_parameters":[],"claims":["iss"],
"messages":[],"description":""},
"scope":"https:\/\/purl.imsglobal.org\/spec\/lti-ags\/scope\/lineitem
https:\/\/purl.imsglobal.org\/spec\/lti-ags\/scope\/result.readonly
https:\/\/purl.imsglobal.org\/spec\/lti-ags\/scope\/score
https:\/\/purl.imsglobal.org\/spec\/lti-nrps\/scope\/contextmembership.readonly"} ◀"
  +requestHeaders: array:6 [▼
    0 => "POST /mod/lti/openid-registration.php HTTP/2"
    1 => "Host: [otherdomain].com"
    2 => "content-type: application/json; charset=UTF-8"
    3 => "authorization: Bearer eyJ0eXAiO[...]Njk1ODIzMT ▶"
    4 => "accept: */*"
    5 => "content-length: 859"
  ]
  +response: "missing_registration_token"
  +responseHeaders: array:4 [▼
    0 => "HTTP/2 401 "
    1 => "server: nginx-rc"
    2 => "date: Wed, 27 Sep 2023 13:58:49 GMT"
    3 => "content-type: text/html; charset=utf-8"
  ]
  +relativeLinks: []
  +status: 401
  +error: ""
  -url: "https://[otherdomain].com/mod/lti/openid-registration.php"
  -method: "POST"
}

As you can see, I receive back a 401 with response: "missing_registration_token".

I do not know what I am missing here. Where should I fill in this registration_token? Is this in Moodle or somewhere else? If in Moodle, can you point what I have to fill in where?

Thanks!