Hello from Malta. I have the title problem with my wordpress (jinnie-femme.eu), where I receive emails for incomplete scans. Based on previous posts, I've ran the connectivity testing tool and the results are the following:
Wordfence connectivity tester DNS lookup for noc1.wordfence.com returns: 220.127.116.11 STARTING CURL http CONNECTION TEST.... Curl connectivity test passed. STARTING CURL https CONNECTION TEST.... Curl connectivity test passed.
Seems that everything is ok. I've just made a new scan and got the same error (even though 2 minutes ago, the test was passed):
[May 20 21:18:30] Contacting Wordfence to initiate scan [May 20 21:18:30] Scan terminated with error: We received an error response when trying to contact the Wordfence scanning servers. The HTTP status code was  and the curl error number was