SharePoint 2010 Search - During Crawl Access Denied failure message on only one web application.

All my web application are SSL enabled. Search crawls for all web application but fails for one web application with "Access is denied. Verify that either the Default Content Access Account has access to this repository, or add a crawl rule to crawl this repository. If the repository being crawled is a SharePoint repository, verify that the account you are using has "Full Read" permissions on the SharePoint Web Application being crawled." message.
Solution Tried
Disable Loopback is already in
The search account has permission to web application and DB as well
Created crawl rule.

But the crawl is successful even with same error message, if i select Ignore SSL warning and increase time to 120 in farm search configuration, but i cant do the same in prod environment.

Kindly help how can i identify the root cause or inner error actual message.