Fix AWS SSH operation Timeout Issue

I'm unable to connect to my AWS instance via SSH. It was working fine until two days ago, and I made no changes to the instance during this time.

Key Details:
- SSH connection times out.
- Security group settings are correct.

I'm looking for an experienced AWS professional who can quickly diagnose and resolve this issue. Ideal skills and experience include:
- Strong knowledge of AWS and SSH
- Experience troubleshooting connectivity issues
- Familiarity with AWS security groups and instance configurations

Please provide a brief overview of your approach and estimated time to resolve.
low budget