Connecting Zoom with LTI 1.3 with Moodle 4.5.3+ (Build: 20250401) always show error 500

Zoom Apps
1

Zoom Apps Configuration
LTI Pro 1.3 with Moodle 4.5.3+ (Build: 20250401)

Description
We’re attempting to configure LTI 1.3 integration for Zoom LTI Pro on two different Moodle sites:

  • :white_check_mark: Success on: siteA.visiniaga.com
  • :cross_mark: Fail on: siteB.visiniaga.com

Both Moodle sites use the same Zoom account and we are following Zoom’s official LTI 1.3 setup documentation. The configuration succeeds on moodledev.visiniaga.com, but returns a 500 Internal Server Error when accessed via cloud.lentera.petra.ac.id.

Error?
On accessing the Zoom LTI Pro tool from Moodle (cloud.lentera.petra.ac.id), we receive:

Internal Server Error  
500 - v=2.0;clid=aw1;rid=INT_d5299e196e151284

The issue appears in the browser console and page load. Zoom dashboard call logs do not show any trace of the error.

Troubleshooting Routes

  • Recreated the external tool and credentials in Moodle.
  • Purged Moodle site caches completely.
  • Tried different browsers (Chrome, Firefox, Incognito mode).
  • Verified there’s no firewall blocking access (site is hosted on GCP).
  • Re-authorized Zoom LTI Pro in the Marketplace.
  • Verified credentials and URLs match working configuration.
  • Compared working and non-working Moodle environments (same configuration logic, both use Zoom LTI Pro app from the same account).

How To Reproduce

  • Log into Moodle site cloud.lentera.petra.ac.id as Admin.
  • Navigate to a course using Zoom as an LTI external tool.
  • Attempt to launch Zoom via the embedded external tool.
  • Result: Page fails with “Internal Server Error 500”.
2

Hey @Lewi
Thanks for reaching out to us! I created a support ticket on your behalf and you will receive an email from our support team soon.

3

Hi Elisa,
Cc Mr. Pur from PCU
Cc Felina from Visiniaga team

Thanks for your email

Sincerely

1 Like
4

got response from support, it seem resolve now, it may cause by ssl certificate upload on gcp load balancer need to combine with ssl chain certificate from issuer

Could you please check

  1. if you have a cert installed on the root path

Fallback occurred JwkClient, jwk-client
feign.RetryableException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target executing GET https://cloud.lentera.petra.ac.id/mod/lti/certs.php

  1. The endpoints below need to be publicly available for us to verify the LTI 1.3 JWT. Have them see if they can make these available:

{domain}/mod/lti/certs.php
{domain}/mod/lti/auth.php
{domain}/mod/lti/token.php

Regards,

Fan

after previously sending HAR file:
4408828867098-Generating-a-HAR-file-for-troubleshooting

1 Like