EC2 instance suddenly stopped working.

Last week, one of my EC2 instances suddenly became unresponsive without any prior changes on my end. Despite trying various troubleshooting steps, such as allowing ports and checking network settings, I couldn't pinpoint the issue. When attempting to SSH into the instance, I encountered the error message: "Failed to connect to your instance. EC2 Instance Connect is unable to connect to your instance. Ensure your instance network settings are configured correctly for EC2 Instance Connect." It's important to note that I haven't made any alterations that could have caused this failure. If anyone has insights or potential solutions, I'd greatly appreciate the assistance.