SignatureDoesNotMatch trying to access SB S3, using authenticated users session token

        "stack": "Error: The request signature we calculated does not match the signature you provided, Check your credentials. The session token should be a valid JWT token\n    at Object.SignatureDoesNotMatch (/app/dist/internal/errors/codes.js:171:39)\n    at Object.<anonymous> (/app/dist/http/plugins/signature-v4.js:82:36)"
      }

let credentials: {
            accessKeyId: string;
            secretAccessKey: string;
            sessionToken?: string;
        } = {
            accessKeyId: config.accessKeyId,
            secretAccessKey: config.secretAccessKey
        }
        if (config.accessKeyId === "vkfwaufurgmyfqrpmnoo") {
            credentials = {
                accessKeyId: "vkfwaufurgmyfqrpmnoo",
                secretAccessKey: 'anonKey',
                sessionToken: config.secretAccessKey
            }
            // console.log("Using secret access key: " + config.secretAccessKey);
        }
        this.s3Client = new S3Client({
            forcePathStyle: true,
            region: config.region,
            endpoint: config.endpoint,
            requestChecksumCalculation: "WHEN_REQUIRED", // to work around the S3 client trying to use the 'File' as a node based ReadableStream
            credentials: credentials,
        });