Not receiving message in Client side (Signalr)

Question

JavaScript ->

connection = new HubConnectionBuilder().withUrl((

connection.on("CampaignMessage", (message) => {
      this.showPopup(message);
    }),

Azure Function (Isolated worker-process) - c#

[Function(SenogInformation("Triggered message to {UserId}", pushNotificationMessage.User);

                    var messageArgument = JsonConvert.SerializeObject(new
                    {
                        pushNotificationMessage.Message,
                        pushNotificationMessage.ResponseEndpoint,
                    });

                    return new SignalRMessageAction(SignalRHub)
                    {
                        Arguments = new[] { messageArgument },
                        UserId = encodedUserId,
                    };
                }
                else
                {
                    this.logger.LogInformation("User {UserId} is offline", pushNotificationMessage.User);
                    this.logger.LogInformation("Storing message to saturation storage");

                    pushNotificationMessage.ExpiryTime = DateTime.UtcNow.AddDays(Convert.ToInt32(this.pushNotificationOptions.Value.MessageExpirationTimeInDays));

                    await this.pushNoticationService.DeliverMessageWhenUserConnectedAsync(pushNotificationMessage);

                    return new SignalRMessageAction(SignalRHub);
                }
            }
            catch (Exception ex)
            {
                this.logger.LogError(ex, ex.Message);
                throw;
            }
        }

Here I'm trying to send message from server side to client side using signalr (Isolated process), but I'm not receiving any message in client side, after sending message to the hub from server side