Discovered while using broken install of zotero that returns internal server error for exports.
To reproduce:
http://localhost:1970/api?format=bibtex&search=http%3A%2F%2Flink.springer.com%2Fchapter%2F10.1007%2F11926078_68
returns
{"status":500,"type":"internal_error","title":"TypeError","detail":"Cannot read property 'response' of undefined","method":"GET","uri":"/api?format=bibtex&search=http%3A%2F%2Flink.springer.com%2Fchapter%2F10.1007%2F11926078_68"}