Build failed with 500, please run 'jupyter lab build' on the server for full output in Jupyter lab
Solution 1:
Using terminal, try jupyter lab build, which will produce an output on your AppData\Local\Temp folder (if you are on Windows). The log file will give more info on what is causing the failure during the build.
I had the same issue and npm dependencies were the culprit. I have updated conda with conda update -n base -c defaults conda and and yarn with conda install yarn and it solved the issue for me.
Also try looking at this one Jupyter Labs: “RuntimeError: npm dependencies failed to install” When Building.