Most LCCN numbers are straight numbers. But this one, https://lccn.loc.gov/a48004732, is an example where the official LCCN is "a 48004732", with a space. The External ID field is not able to interpret this LCCN number correctly, i.e. is not able to get the correct link to that page. The workaround is easy: Just omit the space. But it seems that the system should be able to do that itself if someone entered the "correct" LCCN.
Anonymous
Fixed in common/library.py 1.146, installed in r2017-217 on 2017-05-26. Closing.
Closing for real this time.