EC2 Instance Goes Offline After Running Script but AWS UI shows that everything is OK

Hi all,

I have a t3small instance with Apache2, Mysql, Php 8.2, Docker. After trying to install a package (Pimcore) using Composer it went offline. No response on any port.

I tried:

• Rebooting
• Completely stopping and launching instance
• Changing instance type to one with more memory

What I see:

• Amazon EC2 UI shows status "Running" and 2/2 status checks completed.
• System log doesn't show anything unusual, no process kills (Memory: 1968412K/2057760K available)
• There were no changes in the security group rules associated with the instance

I can't use serial console because I didn't create a password for any OS user and used to connect via SSH.

What do I do?