Greasy Fork镜像

Button on Amazon web page? Where is the button?

I try to import this release https://www.amazon.com/Wings-Song-Narvel-Felts/dp/B00110RMAE to MusicBrainz. I installed your userscript (and it's activated) on Firefox 56.02, but now I don't see any button on the Webpage of Amazon. What can I do to make the button appear (or is the button hidden or am I blind?)

It seems to me that the script with amazon.com doesn't work properly.
See:
https://www.amazon.com/Wings-Song-Narvel-Felts/dp/B00110RMAE
https://www.amazon.com/Seasons-Greetings-Narvel-Felts/dp/B000QQZWCE
https://www.amazon.com/Me-Bobby-Mcgee-NARVEL-FELTS/dp/B000FS9FOO/ref=pd_bxgy_15_img_3?_encoding=UTF8&psc=1&refRID=QVF1PJCGX8Z7P7HK5PJ1
The script sometimes works with amazon.de. See:
https://www.amazon.de/1956-Radio-Rockabillies-Narvel-Felts/dp/B071VTWD4M/ref=sr_1_2?ie=UTF8&qid=1509289424&sr=8-2&keywords=narvel+felts
and sometimes don't:
https://www.amazon.de/Those-Rockabilly-Years-Narvel-Felts/dp/B016OYOY70/ref=sr_1_1?ie=UTF8&qid=1509289424&sr=8-1&keywords=narvel+felts