EC2 Instance Connect doesn't work

Hello, my EC2 Instance Connect doesn't work, saying"Failed to connect to your instance Error establishing SSH connection to your instance. Try again later." Also SSH connect on my computer doesn't work. I tried EC2 serial console connection, but it works very slow and I can't connect successfully either. Also in Instance status checks, Instance reachability check can't pass from time to time. Instance details: Platform Ubuntu (Inferred) IPv4 SSH TCP 22 0.0.0.0/0 – – IPv4 HTTP TCP 80 0.0.0.0/0 outbound rule is allow all traffic from all. Background is that I just increased my volume size from 8g to 12gb, but I didn't increase file system in console. then connection doesn't work somehow. I don't know if it is related. I hope some one can help me!