It works now because I have implemented preemptive authentication. I'll create a ticket, because this is something I think we should support.
I have analyzed the logs once again. MCF never tries to authenticate. Well, it tries, but it cannot repeat the request entity. That's why I mentioned that preemptive authentication could be a solution. Then we only need to post to Solr once, not doing the unnecessary two-step authentication process by: 1. Try to post 2. Solr server sends a 401 response 3. Try to post once again using the header: "Authorization: Basic ******" It's not very effective if you have to post, say, 100,000 documents. This is actually what happens: 1. http-outgoing-200 >> "POST /solr/uio/update/extract HTTP/1.1[\r][\n]" 2. http-outgoing-200 << "HTTP/1.1 401 Unauthorized[\r][\n]" 3. IO exception during indexing https://www.journals.uio.no/index.php/bioimpedance/article/view/3350: null org.apache.http.client.ClientProtocolException (Caused by: org.apache.http.client.NonRepeatableRequestException: Cannot retry request with a non-repeatable request entity.) By using preemptive authentication, the following is now being sent to Solr in the first request: http-outgoing-30 >> "POST /solr/uio/update/extract HTTP/1.1[\r][\n]" http-outgoing-30 >> "Authorization: Basic **************[\r][\n]" Preemptive authentication is also suggested as a solution to other developers facing the same problem: https://developer.ibm.com/answers/questions/266117/im-getting-this-exception-trying-to-add-doc-to-wat/ I can create a patch or PR. It's very easy to implement, and we have done it for all the other Solr connectors we have developed. Erlend
