As requested on issue #1346, I tried the following, but with no success.
jupyter serverextension enable --py jupyterlab --user

This is what I get when I run the --debug

Hi @ktuluv, can you please run conda update jupyterlab to pick up the latest and try again?
@blink1073 Thank you, that worked!!
Great!
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Hi @ktuluv, can you please run
conda update jupyterlabto pick up the latest and try again?