Add troubleshooting guide for authentication issues

This guide is certainly incomplete, but it could serve as starting point
for discussion.

modules/sysadmin_guide/pages/ipsilon.adoc

@@ -11,6 +11,7 @@
 ** <<_openid_connect_scope_registration>>
 ** <<_generate_an_openid_connect_token>>
 ** <<_create_openid_connect_secrets_for_apps>>
+* <<_troubleshooting>>
 
 == Contact Information
 
@@ -213,3 +214,33 @@ variable name to the person who requested it.
 
 Finally, commit and push the changes to both files and run the
 `ipsilon.yml` playbook.
+
+== Troubleshooting
+
+Here is a guide one can follow when trying to troubleshoot authentication
+issues within Fedora Infrastructure for users.
+
+. SSH to ipsilon machine
++
+----
+ssh ipsilon01
+----
++
+. Find the entry in logs
++
+The logs are located in `/var/log/httpd/error_log`. You can find the entry either by
+looking at the timestamps or looking for the `ipsilon_transaction_id`.
++
+If you don't see the error in the ipsilon logs you can continue to next step.
++
+. SSH to IPA machine (usually ipa01)
++
+----
+ssh ipa01
+----
++
+. Look into the logs
++
+On ipa machine the logs could be found in `/var/log/httpd/error_log`, but it's hard to map
+the ipsilon transaction to exact entry in the logs, so you can either map them together by time
+or just looking for any error that seems related.