Hello,
Generally 'Instance Status Check' verifies that your instance's operating system is accepting traffic.
When it fails it means that the operating system inside the instance is not responding to traffic, for example this can happen when a Windows instance hangs or when a Linux instance kernel panics or network is disabled inside the instance.
I had a look at your account and there is one instance in there, looking at the instance it seems that you have rebooted the instance and I could make successful connection to port 22 and 80 on the instance as those ports are open to world.
I also had a look at the underlying host of the instance and could not see any issues on the underlying host. I would recommend you to check system and kernel logs before the reboot to track down what has happened.
'502 Bad Gateway' could also be a sign of the webserver not responding in timely manner, which is in line with the fact that CloudWatch has recorded constant 100% CPU usage for your instance.
Given the fact that your instance is a t.micro instance, if the high load is legitimate you may want to consider migrating to a larger instance type like m1.small for example.
Kind regards,
Mostafa S.

Thank for your advice.
Let me try to migrate it to other larger instance.
If it still get a problem i will reach you again.
Regards,

Hi Mostafa S,
I would like to inform you one more thing that sometime my website appear an error message '504 Gateway Time-out'.
What is this message about?
Regards,
Han
Edited by: hychanhan on Jan 5, 2014 7:32 AM

Hello,
Thank you for the update. I would like to investigate your ec2 server, however, I might need more information from you. Can you please provide me with your ec2 instance ID?
Regards,
Marcin

Hi Marcin,
I have solved the problem already.
The problem caused from my server was running out of storage.
And now I just created another snapshot for a new volume 25GB more.
It is working fine now.
Thank you so much.

Best Regards,
ChanHan

EC2 instance stuck in 'stopping' state, pls resolve it
Hi EC2 support,
My EC2 instance, stops all the time, so I have to manually reboot it through the AWS EC2 Management Console. That's a huge problem, because, as a result my webpage stops working, pretty much plenty times per day too, along with my EC2 instance, because if I try to ssh, I'll always get 'ssh_exchange_identification: read: Connection reset by peer', while my instance is in that state . Please, get it resolved.
My instance id is: i-06b8743cb2461b1dd
Thanks,
Mil

Hi,
My site giving 502 bad gateway.pls help.instance id is. i-04dc8c91a36f3b1a7
Now i stated getting database error.
We didnot change any credentials.
Please check if database is up and running.