Unable to even select "Export PDF" in Adobe Export PDF

I pay for Adobe Export PDF, which I use through my Adobe Acrobat Reader DC. I have used it fine in the past to convert PDFs to Word documents. But for some reason, now I cannot even select Export PDF (or Create PDF, Edit PDF, Combine Files, Organize Pages) from the list along the right. When I click on "Export PDF," the arrow next to it (for a drop-down menu?) switches to up or down, but nothing else happens. Right-clicking and selecting "Open" also does nothing.

I almost wondered whether I'd been locked out due to failure to pay, but no, I renewed with a new card and was charged back in July for a new year. And at the bottom right of the window, it says "Your current plan is Adobe Export PDF." What might be the problem?