Sometime server failed

I want to confirm about jitsi server.
I use Ubuntu 18.04 LTS from aws ec2.
Everything is fine. We already used it.
But now sometimes I face when I access my domain, This site can’t be reached.
When I reboot my instance, that problem is gone.
But I want to know that problem is related jitsi meet or AWS ?
Btw, my dns is use another service I mean it not from AWS route53.
Thanks in advance.