Server Not Running (Kernel Restarting issue)

running jupyter/datascience-notebook:1386e2046833 on Jupyterhub (with EKS on AWS)

getting the following error : Server Not Running : Your server at /jh/users/<username>/ is not running. Would you like to restart it ?

in the Jupyterhub logs i have the following message :
SingleUserLabApp zmqhandlers:182] WebSocket ping timeout after 90002 ms
SingleUserLabApp kernelmanager:217] Starting buffering for 533a90f9-e00f-4019-8044-59727faba7a5:de0312ca-a1f7-478b-a24a-1fe22593ec5f
kernelmanager:172] Kernel started: 1d7deac9-4b49-49c4-913c-490b6cb1d754