Suddenly cannot SSH into established EC2 instances in US-East-1

Having trouble SSH'ing into multiple, long-running EC2 instances in US-East-1. This instances have been running fine with zero trouble for years.

Getting connection timeout on port 22. Other services (web, mysql) are still working fine.

SSH'ing fails both from the linux command line (standard SSH client) and from the AWS console website (just get a black screen with no response).

Also tried rebooting the instance, and I've checked my security group configuration (allowing access on port 22 both to my ip address and to any ip address).

CRITICAL ISSUE. Please address with feedback that the problem is being investigated or suggestions for what else I can do on my end.

Edited by: JohnDeLancey on Jun 27, 2020 7:37 AM