A newly installed tunnel client is not connecting to the tunnel server. Other clients connect fine; this client fails to connect and the following message is seen in the hub.log:
Feb 18 11:10:32:570  1 hub: SSL using cipher: DHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=DH Au=RSA Enc=AESGCM(256) Mac=AEAD
Feb 18 11:10:37:582  0 hub: CTRL send message failed for get id command
Feb 18 11:10:37:582  0 hub: CTRL failed to get ID from ##.##.##.##/48003
Feb 21 14:59:07:304  0 hub: CTRL send message failed for new conn command (ip:port)
Feb 21 14:59:07:304  2 hub: CTRL hubname new (inner) connection failed
Release : 20.3
Component : UIM - HUB
Check the default MTU Settings on the Ethernet interface of the tunnel client.
If it is not set to the normal default value of 1500 it may cause this issue.
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 8900
[root@myserver]# ifconfig eth0 mtu 1500
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
Additionally, this issue may be seen if the tunnel certificate is corrupt, or the hub.cfg is not pointing to the correct pem file.
If the MTU issue above is not the cause then it is recommended to delete the certificates and tunnel configuration on the client side and re-configure it.