Hello @Erik H
Thanks for the question and using MS Q&A platfrom.
Please check this thread that mentions it to be a known issue and the fabric product team is working on it https://community.fabric.microsoft.com/t5/Data-Engineering/Notebooks-Cluster-failing-to-start-Livy-session-error-North/m-p/4045984
Please note MS Fabric is currently not supported in the Q&A forums, the supported products are listed over here Supported products on MS Q&A (more to be added later on).
You can ask the experts in the dedicated MS Fabric community forum.
Can you please open as a new thread in MS Fabric community: https://community.fabric.microsoft.com/t5/General-Discussion/bd-p/ac_generaldiscussion
Also you can refer to similar issues reported in the past here https://community.fabric.microsoft.com/t5/Data-Engineering/Notebook-fails-with-error-200-when-run-from-Pipeline/m-p/3756263
Hope this helps. Do let us know if you any further queries.
--please don't forget to "[Accept the answer]" if the reply is helpful--