blocked network interface

I'm not Italian, sorry :)

It could be that the web server process stopped for some reason, which could explain why the website was not available until a restart. I believe the web server logs would be a good place to start in that case.

If I understand it correctly, the application running in the instance is still working, but you cannot connect to the instance remotely, with SSH for example.

There could be several reasons for that - the instance being on a private network and your VPN connection not working, security group does not have the appropriate input rules configured, SSH daemon isn't running, to name a few.

Additional context would be helpful, e.g. what is meant by "the machine is working properly" - does this mean you have an application running on it and can validate that this is still working, or does it just mean all Instance Status Checks are green, for example? By the instance "not being reachable", do you mean you get a specific error condition when connecting to it with a given protocol or does the connection just hang indefinitely? Is the instance running Windows or Linux (which flavor)?

I find it hard to point in a specific direction as it stands, so hopefully this documentation helps:

• https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-console.html
• https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Linux-Server-EC2Rescue.html
• https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/screenshot-service.html
• https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/Windows-Server-EC2Rescue.html

correct objections. The instance is a Linux that publishes a website. The machine is reachable via the AWS console but is not reachable on the web side from outside. Once a restore has been performed it restarts and runs again correctly The machine has been working correctly for months and nothing has been changed on the machine since this problem arose (about 2 months)

Marco, ma sei italiano?