Signature Invalid error with new General App (Meeting SDK) - Works with old apps

Meeting SDK
1

Hi Zoom Developers,

I am experiencing a “Signature is invalid” when trying to join a meeting using the Web Meeting SDK with a newly created General App.

Context:

  • App Type: General App (Draft status).

  • Environment: Web Meeting SDK (testing with the official Sample Web App).

  • Behavior: I can successfully authenticate via OAuth and create meetings using the API, but the signature generated for the SDK is rejected.

  • Comparison: Using the exact same backend logic with an older SDK app, the signature works perfectly.

My Signature Payload: I am using the following structure for the JWT:
```
{
sdkKey: ‘UHOpylvURU6MlUhM4WB5gg’,
mn: 81483210008,
role: 1,
iat: 1770047168,
exp: 1770054368,
tokenExp: 1770054368
}
```
What I’ve checked so far:

  1. I am using the Client ID as the sdkKey.

  2. I am using the Client Secret to sign the JWT with HMAC SHA256.

  3. The iat is in seconds and I’ve accounted for clock drift (minus 60 seconds).

  4. The meeting was created by the same account that owns the App.

  5. The domain is added to the “OAuth Allow List” in the Marketplace.

Is there any specific requirement for General Apps (unified apps) that differs from the older Meeting SDK apps regarding signature validation?

Thanks in advance!