EC2 Status check failed a few times

Status checks fails due to one of many reasons.. some of them below;.. Resource limitations: It is possible that the default limits for some of the AWS resources associated with your instance, such as the number of Elastic IP addresses, security groups, or network interfaces, have been reached. To verify this, you can check the AWS documentation for EC2 instance limits or contact AWS support.

Issues with the OS or kernel: It is possible that your Ubuntu operating system or kernel is experiencing errors or issues that are causing the instance to go down. You can try reviewing the system logs to identify any issues.

Hardware issues: If the underlying hardware of your EC2 instance is failing, this could cause the instance to go down regularly. You can review the EC2 instance system log to identify any hardware error messages.

Network connectivity issues: If there are connectivity issues between the instance and other resources such as a database, web server or Elastic Load Balancer, it can cause the instance to be unresponsive.

AWS Maintenance activities: AWS regularly schedules maintenance activities that require rebooting the instances. If the maintenance event is being performed, then it could be the reason for the instance to go down.

Though reboot works some times (state refesh, network issue fixes, or some new changes can be fixed with reboot), might not work always.. see this documentation for more info..

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html