# Jupyterlab kernel goes to unknown state while using visual debugger ipykernel version 6.4.2

**URL:** <https://discourse.jupyter.org/t/jupyterlab-kernel-goes-to-unknown-state-while-using-visual-debugger-ipykernel-version-6-4-2/13422>\
**Category:** JupyterHub\
**Tags:** kernel-gateway\
**Created:** [March 15, 2022, 12:46pm UTC](https://discourse.jupyter.org/t/jupyterlab-kernel-goes-to-unknown-state-while-using-visual-debugger-ipykernel-version-6-4-2/13422 "2022-03-15T12:46:06Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Putta\_Sumanth\_Reddy](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/putta_sumanth_reddy/32/6719_2.png) [@Putta\_Sumanth\_Reddy](https://discourse.jupyter.org/u/Putta_Sumanth_Reddy)\
**Post date:** [March 15, 2022, 12:46pm UTC](https://discourse.jupyter.org/t/jupyterlab-kernel-goes-to-unknown-state-while-using-visual-debugger-ipykernel-version-6-4-2/13422/1 "2022-03-15T12:46:06Z")

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Am using jupyterlab version 3.0 with python 3.7 & ipkernel 6.4.2, while run script in debug mode, suddenly kernel is going to unknown state, i checked logs it displaying following message…

[E 2022-03-15 11:56:05.004 SingleUserLabApp mixins:538] Error notifying Hub of activity  
Traceback (most recent call last):  
File “/opt/conda/envs/jhub/lib/python3.7/site-packages/jupyterhub/singleuser/mixins.py”, line 536, in notify  
await client.fetch(req)  
tornado.httpclient.HTTPClientError: HTTP 403: Forbidden  
[D 2022-03-15 11:56:05.160 SingleUserLabApp handlers:228] Nudge: attempt 55 on kernel 29587fc0-14cb-45b7-8394-8ccbbb6e14ed  
[D 2022-03-15 11:56:05.661 SingleUserLabApp handlers:228] Nudge: attempt 56 on kernel 29587fc0-14cb-45b7-8394-8ccbbb6e14ed  
[D 2022-03-15 11:56:06.163 SingleUserLabApp handlers:228] Nudge: attempt 57 on kernel 29587fc0-14cb-45b7-8394-8ccbbb6e14ed  
[D 2022-03-15 11:56:06.664 SingleUserLabApp handlers:228] Nudge: attempt 58 on kernel 29587fc0-14cb-45b7-8394-8ccbbb6e14ed  
[D 2022-03-15 11:56:07.166 SingleUserLabApp handlers:228] Nudge: attempt 59 on kernel 29587fc0-14cb-45b7-8394-8ccbbb6e14ed  
[D 2022-03-15 11:56:07.436 JupyterHub log:189] 200 GET /jhub/hub/health (@35.191.15.140) 0.68ms  
[W 2022-03-15 11:56:07.667 SingleUserLabApp handlers:228] Nudge: attempt 60 on kernel 29587fc0-14cb-45b7-8394-8ccbbb6e14ed  
[D 2022-03-15 11:56:08.169 SingleUserLabApp handlers:228] Nudge: attempt 61 on kernel 29587fc0-14cb-45b7-8394-8ccbbb6e14ed