Invalid sdk key error

var iat = ToTimestamp(DateTime.UtcNow.ToUniversalTime()) - 30000;

iat in milliseconds ??? (30000 ms)

var exp = iat + 7200;

now you add 2 hours in seconds ??? (7200 seconds)

SDK JWT Signature:

there is no c# example yet

but here is a javascript example for generating signature for SDK JWT

https://marketplace.zoom.us/docs/sdk/native-sdks/auth/

here another javascript example

and here a php example