Changing the languages in the dialog window multiple times, while also running the code blocks before the kernel is initialized seems to kill the kernel connection for me. In my console, the kernel will attempt to reconnect to the kernel every x number of seconds, but will fail to do so.
This only seems to happen on my computer, and more often in Firefox than Chrome. It might be due to a flaw on my computer locally.
The TypeError error may be associated with clicking OK before the kernel is connected.
-@celine168