Can't access US-East-1 region

Check the AWS Service Health Dashboard for any current issues or maintenance affecting the US-East-1 region. The dashboard will provide updates on any issues.

Verify that the necessary security group rules and route tables allow access to the instances. For example, check that the security groups attached to the instances allow inbound access on the required ports from your IP address or network. Also check that the route tables for the subnets have a route to an Internet gateway.

Try accessing the instances using the AWS CLI or SDK instead of the management console to rule out any console-specific issues:

aws ec2 describe-instances --region us-east-1

Check for any configuration changes that may affect access, such as changed security group rules, route tables, NACLs, etc.

If the issue is still occurring, create a new support case with AWS providing details of the instance IDs, configurations, and exact errors encountered. Their support engineers can assist further with troubleshooting.