We have a problem - after stopping ec2, the nodes do not start again. Playable on three jenkins servers. One of them is clean with plugin Amazon EC2. 

Plugin settings and access to ec2 are the same

Common settings on plugin EC2

Idle termination time: 30

Stop/Disconnect on Idle Timeout: yes

Minimum number of instances: 0

Minimum number of spare instances: 0
Host key Verification Strategy: Off

Connection stratagy: PublicDNS

When I checked credentials and AMI - plugin says - success

Logs on one node when I launch

2020-12-28 12:33:18.949+0000 [id=25] INFO h.p.ec2.EC2RetentionStrategy#internalCheck: Idle timeout of EC2 (Test Amazon connection) - Jenkins PHP70 (same-instance-id) after 30 idle minutes, instance statusRUNNING
2020-12-28 12:33:18.950+0000 [id=25] INFO h.plugins.ec2.EC2AbstractSlave#idleTimeout: EC2 instance idle time expired: same-instance-id
2020-12-28 12:33:19.220+0000 [id=25] INFO h.plugins.ec2.EC2AbstractSlave#stop: EC2 instance stop request sent for same-instance-id
2020-12-28 12:38:01.182+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Launching instance: same-instance-id
2020-12-28 12:38:01.183+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: bootstrap()
2020-12-28 12:38:01.184+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Getting keypair...
2020-12-28 12:38:01.184+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Using private key jenkins (SHA-1 fingerprint same-fingerprint)
2020-12-28 12:38:01.184+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Authenticating as jenkins
2020-12-28 12:38:01.286+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Connecting to null on port 22, with timeout 10000.
2020-12-28 12:38:01.287+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Failed to connect via ssh: There was a problem while connecting to null:22
2020-12-28 12:38:01.288+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Waiting for SSH to come up. Sleeping 5.
2020-12-28 12:38:06.363+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Connecting to null on port 22, with timeout 10000.
2020-12-28 12:38:06.364+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Failed to connect via ssh: There was a problem while connecting to null:22
2020-12-28 12:38:06.364+0000 [id=1078] INFO hudson.plugins.ec2.EC2Cloud#log: Waiting for SSH to come up. Sleeping 5.

On other jenkins server launch says:

Dec 28, 2020 7:15:36 AM hudson.plugins.ec2.EC2Cloud
INFO: Connecting to private-ip-ec2-instance.compute.internal on port 22, with timeout 10000.
Dec 28, 2020 7:15:36 AM hudson.plugins.ec2.EC2Cloud
INFO: Failed to connect via ssh: There was a problem while connecting to private-ip-ec2-instance:22
Dec 28, 2020 7:15:36 AM hudson.plugins.ec2.EC2Cloud
INFO: Waiting for SSH to come up. Sleeping 5.