I'm working on Sumsub SDK implementation, getting an error with SNSErrorHandler class

I'm working on Sumsub SDK implementation, getting an error with SNSErrorHandler class. It's saying to define SNSAppActivity in Android Manifest.xml file.

private void launchSdk(String accessToken, TokenExpirationHandler tokenUpdater) {//accessToken is coming from server (end pole) side.

    List<SNSModule> modules = Arrays.asList(new SNSProoface());
    Context applicationContext = context.getApplicationContext();

    SNSErrorHandler errorHandler = e -> {//Here I am getting error, It's saying to define SNSAppActivity in your Manifest.xml file
        Timber.d("The SDK throws an exception. Exception: %s", e);

        if (e instanceof SNSException.Api) {
            Timber.d("Api exception. %s", ((SNSException.Api) e).getDescription());
        } else if (e instanceof SNSException.Network) {
            Timber.d(e, "Network exception.");
        } else if (e instanceof SNSException.Unknown) {
            Timber.d(e, "Unknown exception.");
        }
        Toast.makeText(applicationContext, "The SDK throws an exception. Exception: " + e, Toast.LENGTH_SHORT).show();
    };

    SNSStateChangedHandler stateChangedHandler = (previousState, currentState) -> {

        Timber.d("The SDK state was changed: " + previousState + " -> " + currentState);

        if (currentState instanceof SNSSDKState.Ready) {
            Timber.d("SDK is ready");
            parseStatus(currentState);
        } else if (currentState instanceof SNSSDKState.Failed.Unauthorized) {
            Timber.e(((SNSSDKState.Failed.Unauthorized) currentState).getException(), "Invalid token or a token can't be refreshed by the SDK. Please, check your token expiration handler");
            parseStatus(currentState);

        } else if (currentState instanceof SNSSDKState.Failed.Unknown) {
            Timber.e(((SNSSDKState.Failed.Unknown) currentState).getException(), "Unknown error");
            parseStatus(currentState);
        } else if (currentState instanceof SNSSDKState.Initial) {
            Timber.d("No verification steps are passed yet");
            parseStatus(currentState);

        } else if (currentState instanceof SNSSDKState.Incomplete) {
            Timber.d("Some but not all verification steps are passed over");
            parseStatus(currentState);
        } else if (currentState instanceof SNSSDKState.Pending) {
            Timber.d("Verification is in pending state");
            parseStatus(currentState);

        } else if (currentState instanceof SNSSDKState.FinallyRejected) {
            Timber.d("Applicant has been finally rejected");
            parseStatus(currentState);
        } else if (currentState instanceof SNSSDKState.TemporarilyDeclined) {
            Timber.d("Applicant has been declined temporarily");
            parseStatus(currentState);

        } else if (currentState instanceof SNSSDKState.Approved) {
            Timber.d("Applicant has been approved");
            parseStatus(currentState);
        }

        if (currentState instanceof SNSSDKState.ActionCompleted) {
            SNSSDKState.ActionCompleted actionState = (SNSSDKState.ActionCompleted) currentState;
            String actionId = actionState.getActionId();
            FlowActionType type = actionState.getType();
            String answer = actionState.getAnswer();
            Map<String, Object> payload = actionState.getPayload();
        }
    };

    SNSCompleteHandler completeHandler = (result, state) -> {
        Timber.d("The SDK is finished. Result: " + result + " , State: " + state);
        Toast.makeText(applicationContext, "The SDK is finished. Result: " + result + ", State: " + state, Toast.LENGTH_SHORT).show();

        if (result instanceof SNSCompletionResult.SuccessTermination) {
            Timber.d(result.toString());
        } else if (result instanceof SNSCompletionResult.AbnormalTermination) {
            Timber.d(((SNSCompletionResult.AbnormalTermination) result).getException());
        }
    };

    SNSActionResultHandler actionResultHandler = (actionId, actionType, answer, allowContinuing) -> {
        Timber.d("Action Result: actionId: " + actionId + ", answer: " + answer);
        return SNSActionResult.Continue;
    };

    SNSEventHandler eventHandler = snsEvent -> {
        if (snsEvent instanceof SNSEvent.SNSEventStepInitiated) {
            Timber.d("onEvent: step initiated");
        } else if (snsEvent instanceof SNSEvent.SNSEventStepCompleted) {
            Timber.d("onEvent: step completed");
        }
    };

    SNSSupportItem supportItem = new SNSSupportItem(
            R.string.sns_support_title,
            R.string.sns_support_subtitle,
            SNSSupportItem.Type.Email, "support@company.com", null,
            SNSIconHandler.SNSCommonIcons.MAIL.getImageName(), null);

    try {

        SNSMobileSDK.SDK snsSdk = new SNSMobileSDK.Builder(context)
                .withBaseUrl(apiUrl)
                .withAccessToken(accessToken, tokenUpdater)
                .withDebug(true)
                .withModules(modules)
                .withCompleteHandler(completeHandler)
                .withErrorHandler(errorHandler)
                .withStateChangedHandler(stateChangedHandler)
                .withActionResultHandler(actionResultHandler)
                .withEventHandler(eventHandler)
                .withSupportItems(Collections.singletonList(supportItem))
                .withConf(new SNSInitConfig("support@gmail.com", "+910000000000", null))
                .build();

        snsSdk.launch();

    } catch (Exception e) {
        Timber.e(e);
    }
    showProgress(false);

}