(404) Not Found Errors when Classifying Documents
Problem
When you run the Cognitive Toolkit Crawler, while assigning Classifications (either as part of a crawl, or when you are doing "Classify in Place"), if you see "The remote server returned an error: (404) Not Found" message in the log, it is most likely because the Classifier is expecting a Document Classifier that is named "default". If you have a classifier there, but named something other than "default", this is easy enough to fix:
Solution
Navigate to your v2 Admin Panel / Cognitive Tools / Document Classifiers
Rename the Classifier to "default"
Click Save