Help! My AWS EC2 Instance Became Unreachable, What Should I Do?

You mentioned RDP, which suggests you're using a Windows instance. Have you checked the monitoring tools available in the AWS console? Look for things like CPU usage—if it spikes, that could be your problem. Also, can you ping the instance? If you're getting a timeout, that could help pinpoint the issue.

In addition to memory issues, it’s crucial to consider that your server may have experienced a breach if it started acting up abruptly without any recent changes. Check for any unusual processes that might be consuming resources. It could also be beneficial to increase your instance capacity or set up monitoring through CloudWatch to keep tabs on memory usage and identify if something suspicious is happening.

This kind of issue often leads back to running out of memory. It's a good idea to monitor your memory usage. If you're consistently hitting the limits, consider spinning up your instance with an upgraded memory option to see if that alleviates the issue. Both Linux and Windows can suffer from this, so it’s worth testing!

If both your old and new instances are experiencing the same trouble, it’s likely not the instances themselves but rather something related to your network configuration. Make sure to check your Security Groups and Network ACLs, as they can block inbound/outbound traffic. Route tables might also be worth reviewing. If you determine it's a recurring network issue, consider using S3 and CloudFront for static sites instead of EC2—it can simplify things!

It sounds like you're experiencing some common EC2 connection issues. I recommend checking out AWS's troubleshooting guide for EC2 issues if you haven’t already. It covers a lot of ground and might help you identify the root of your problem. If problems persist, you might want to explore other resources available for help.