LTI 1.1 Custom Integration – Learner role suddenly failing with 401 error while Instructor still works

App Marketplace
1

We are experiencing a sudden issue with our custom LTI 1.1 integration with Zoom, and we are hoping you can help us identify the cause.

We are not using a standard LMS. This is a custom third-party platform called Classlife, acting as an LTI 1.1 Tool Consumer.
Students and instructors do not have Zoom accounts and access Zoom exclusively via LTI launch validation.

The problem started suddenly across all our client integrations, without any changes on our side.

Issue Summary

  • Instructor launches work correctly

  • Learner launches fail with HTTP 401

  • The only difference between both launches is:

    • roles=Instructor vs roles=Learner

    • User personal data

  • Same consumer key, secret, tool configuration, and endpoint

Zoom error code shown:

int_edu_afad3110-51c8-491e-aad1-1d8679e86d2b

Working LTI Launch (Instructor)

user_id=1
&course=100248
&roles=Instructor
&resource_link_id=room100248
&resource_link_title=Collaborate
&resource_link_description=Collaborate
&lis_person_name_full=Classlife++Educación+
&lis_person_name_family=Educación+
&lis_person_name_given=Classlife+
&lis_person_contact_email_primary=francesc@classlife.es
&lis_person_sourcedid=school.edu:user
&context_id=Classlife100248
&context_title= Música 1r - Classlife Education - #100248
&context_label=100248
&tool_consumer_instance_guid=classlife.education
&tool_consumer_instance_description=Classlife Education
&lti_version=LTI-1p0
&lti_message_type=basic-lti-launch-request
&oauth_callback=about:blank
&oauth_consumer_key=REDACTED
&oauth_version=1.0
&oauth_nonce=6968a9e7b40349.44083835
&oauth_timestamp=1768466919
&oauth_signature_method=HMAC-SHA1
&oauth_signature=REDACTED

Failing LTI Launch (Learner)

user_id=209
&course=100248
&roles=Learner
&resource_link_id=room100248
&resource_link_title=Collaborate
&resource_link_description=Collaborate
&lis_person_name_full=Sofia Miranda
&lis_person_name_family=Miranda
&lis_person_name_given=Sofia
&lis_person_contact_email_primary=francesc@classlife.es
&lis_person_sourcedid=school.edu:user
&context_id=Classlife100248
&context_title= Música 1r - Classlife Education - #100248
&context_label=100248
&tool_consumer_instance_guid=classlife.education
&tool_consumer_instance_description=Classlife Education
&lti_version=LTI-1p0
&lti_message_type=basic-lti-launch-request
&oauth_callback=about:blank
&oauth_consumer_key=REDACTED
&oauth_version=1.0
&oauth_nonce=6968a96392d7a8.19415644
&oauth_timestamp=1768466787
&oauth_signature_method=HMAC-SHA1
&oauth_signature=REDACTED

Additional Notes

  • This affects all our customers simultaneously

  • No configuration or code changes were made on our side

  • Credentials and LTI configuration are unchanged

  • We have attached screenshots showing:

    • Instructor access working

    • Learner access failing

    • Full credential configuration in LTI Pro

Questions

  1. Has there been any recent change in Zoom’s LTI role validation?

  2. Is roles=Learner still fully supported for account-less users?

  3. Are there any new required parameters or restrictions for Learner launches?

  4. Is there a way to obtain more detailed OAuth signature validation logs for this error?

Thank you very much for your help.

Best regards,
Classlife Team

2

The “launch_presentation_locale” field has now become mandatory for the Learner role, despite the fact that neither the LTI 1.1 specification nor the Zoom LTI PRO documentation lists it as required, and no official policy update has been communicated.