Connection Timeout Error while connection EC2 with Putty

Did you add your ppk key to Putty? You need to convert .pem key from AWS to .ppk file.

You can refer to this https://support.cloudacademy.com/hc/en-us/articles/360036151511-How-do-I-convert-a-PEM-Key-to-a-PPK-Key

A timeout indicates that the EC2 instance isn't reachable. If the key was incorrect you'd see an error messaging indicating that.

Things I would try:

• See if you can SSH to other destinations; if your service provider may be blocking outbound SSH connections from your network.
• Use the EC2 Serial Console to check that the instance is running the SSH daemon.
• See if you can SSH from the instance to itself.
• Set up another EC2 instance in the same VPC. Use the Serial Console again to see if you can SSH within the VPC.