Amazon Connect GetTranscriptCommand getting 403 error

I'm trying to get a transcript from Amazon Connect on the backend side, however, I'm getting a 403 permission denied error.

Here's the code I'm using:

import { ConnectParticipantClient, CreateParticipantConnectionCommand, GetTranscriptCommand } from "@aws-sdk/client-connectparticipant";

const client = new ConnectParticipantClient({
  region: 'us-west-2'
});

const createConnectionInput = {
  ParticipantToken: "participant-token", // obtained from StartChatContact
  Type: ["WEBSOCKET", "CONNECTION_CREDENTIALS"]
};

const createConnectionCommand = new CreateParticipantConnectionCommand(createConnectionInput); 

After we are getting and 403 error

CreateParticipantConnectionCommand AccessDeniedException: 
Unable to determine service/operation name to be authorized

The remaining part of code just to provide a full picture

try {
  const createConnectionResponse = await client.send(createConnectionCommand);
  const connectionToken = createConnectionResponse.ConnectionCredentials.ConnectionToken;

  const transcriptInput = {
    ContactId: "contact-id",
    ConnectionToken: connectionToken,
  };

  const transcriptCommand = new GetTranscriptCommand(transcriptInput);
  const transcriptResponse = await client.send(transcriptCommand);
  console.log("Transcript retrieved successfully:", transcriptResponse);
} catch (error) {
  console.error("Error:", error);
}

The documentation I've used

https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/connectparticipant/command/CreateParticipantConnectionCommand/


https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/connectparticipant/command/GetTranscriptCommand/



Does this possibility exists? Am I doing smth wrong?

Thanks!