Application not coming up in stopping and restarting EC2 instance under ASG

Question

I have a requirement where I need to stop EC2 instance in non-working hours.My EC2 instances are under ASG. For this, I have written an python script and followed below steps:

1. Get the ASG name from boto3:

   describe_auto_scaling_groups

2. Then Suspend ASG :

   asg_client.suspend_processes(AutoScalingGroupName=asg['AutoScalingGroupName'], ScalingProcesses=['Launch', 'Terminate', 'AZRebalance', 'ReplaceUnhealthy', 'HealthCheck'])

3. Stopping the EC2 instances under ASG by following command:

   ec2_client.stop_instances()

Then restarting the server again after Non - business hours following below steps:

1. Get ASG name using below:

   describe_auto_scaling_groups

2. Start the EC2 instances under this ASG using below:

   ec2_client.start_instances()

3. Resume ASG:

   asg_client.resume_processes(AutoScalingGroupName=asg['AutoScalingGroupName'])

But after restarting the EC2 instances, application inside the instance in not coming up automatically.

If I don't suspend ASG and allow ASG to terminate and launch a new EC instance by manually stopping the instance and then ASG creating a new instance, then no issues in application coming up automatically in the new instance.

Can someone please guide me here.