I was having this error generated from my SharePoint 2013 Crawl Log saying the HTTP response is not recognised when it was trying to crawl my SharePoint Webs
This error came out after configuring a subscribed SSL certificate from Entrust (it may happen to all other vendor too I bet) in IIS.
After digging the Application Log of my SharePoint 2013 server which is running the crawling, Error like below was shown:
An operation failed because the following certificate has validation errors: Subject Name: CN=xxxx, OU=XXX. Thumbprint: xxx Errors: PartialChain: A certificate chain could not be built to a trusted root authority. RevocationStatusUnknown: The revocation function was unable to check revocation for the certificate. OfflineRevocation: The revocation function was unable to check revocation because the revocation server was offline.
After reading this error message, it reminds me that I have a chain certificate provided by the SSL vendor which it is asked to import this chain to my server’s certificate store
For SharePoint, You will need to do additional steps to configure this! If you happen to see this error, please kindly perform the following steps:
- Import the Chain Certificate from your SSL vendor and save into your server.
- Go to Central Admin > Security > Manage Trust
- Click “New” in the Trust Relationships tab
- Enter the name for the trust and browse the imported Chain Certificate.
- Click Ok to create the trust. You shall see your new trust being added
- Perform a full crawl again and you shall see the Crawl Log starts generating results
Note: Ticking the “Ignore SSL Warning” in Farm Search Administration page does not help. Have tried that and it didn’t work. The above steps should suffice.