XD it Flutter plugin not exporting widgets

Question

I am using Adobe XD by installing XD to Flutter, a plugin. But suddenly, there is no response when I click Export All Widgets or Export Widget. I'm flustered because it worked until just a moment ago.

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I managed other settings, turning those settings off and on, and saved the file again as a different name, but there is still no response. The only difference is that elements are grouped in Xd.