Searching DNB for existing ISBN returns empty result

Created by: workflowsguy

When searching DNB from the command line for an ISBN that has associated book data, it returns "No results found".

Steps to reproduce

Input: "/Applications/calibre.app/Contents/MacOS/fetch-ebook-metadata" -i 9783641042738 -p DNB_DE

Output: <calibre.utils.logging.ThreadSafeLog object at 0x116555650> No results found

Expected: Book data for title "Die Neuromancer-Trilogie : Roman / William Gibson" as is shown on https://portal.dnb.de/opac.htm?query=9783641042738&method=simpleSearch&cqlMode=true

Other ISBNs I found with the same issue:

9783833869907 9783709306406

Calibre version 3.48 on macOS 10.13.6