Create signature in c# returns "invalid signature"

I am using framework .NET 5.0 to host a meeting in Zoom.
WebSDK is used.
Zoom pro account is used
Jwt already created and used

There’s an error “invalid signature” when it is created using C# example. I have tried create the meeting manually in Zoom Account, then join the meeting and the error happen again.

Invalid signature when C# example
When I use ZoomMtg.generateSignature in client works fine.

Which version?


  • Browser: Chrome

I have followed these links without luck:

Any help will be great


Hey @amc ,

Can you please provide your Web SDK signature for a test meeting to so I can help you debug it? :slight_smile:


Hello @tommy the signature is:

These are the error messages:


Any idea, seems the signature added here is gone. I share another one:

Still having problems to host or join a meeting. This signature is to create one as a host.


Hey @amc ,

Your signature looks correct. Let me ask you this, are you trying to start a meeting you own, or a meeting that is owned outside of your account?

More info here:


Hi @tommy I have tried start (host) then join a meeting using my API Key and API Secret.

Also I have tried join a meeting created manually using zoom portal

Using a schedule meeting:

Using Host a meeting directly in the menu:

Both without success yet.

Please your comments


Hey @amc ,

I am going to send you a private message so we can assist further.


For others reference, I am sharing the solution here per @amc :

I just saw in the documentation that these couple of lines were added:

string msgHashPreHmac = System.Convert.ToBase64String (messageBytesTest);
byte[] messageBytes = encoding.GetBytes (msgHashPreHmac);

So I added and tested, now I am able to host and join meetings :sunglasses: !


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