Git HTTPS access hangs and doesn't work

We have a self-hosted omnibus install of Gitlab and for the last few weeks Git HTTPS access hangs and never works. Git SSH access works fine, and web HTTPS access works fine. We use LDAP for user authentication. It looks like the authentication is working, but after that the clone/pull hangs and never finishes. I can’t find any errors in the logs, but searching the logs is pretty difficult since they spew lots of spurious information.

OK, I have tracked things down to gitlab-workhorse hanging. The logs show the initial request but don’t show any more log output that I can tell. How can I debug the authbackend that is used by gitlab-workhorse. I am assuming there is something wrong there.