Add troubleshooting page, add cross-reference from Tutorial, remove orphaned integration pages from Tutorial directory.

docs/tutorial/installing_kumomta.md

@@ -166,3 +166,5 @@ sudo KUMOD_LOG=kumod=info /opt/kumomta/sbin/kumod --policy /opt/kumomta/etc/poli
 ```
 
 If all goes well, it should return a PID and drop you back to a Linux prompt.
+
+If KumoMTA does not start, refer to the [Troubleshooting Page](../userguide/operation/troubleshooting.md) of the User Guide.

docs/tutorial/integrate_ongage.md

@@ -1,53 +0,0 @@
-# Ongage SMTP integration  
-
-
-## Get KumoMTA 
-
-1. Install KumoMTA as per the installation instructions here  
-https://docs.kumomta.com/userguide/installation/overview/ 
-
-Before finishing this step, you should ensure that you have correctly set up DNS with a resolving sending domain, MX, PTR, SPF, DKIM, etc.   
-
-As part of this process, you will be creating a DNS entry for “bounce.<yoursendingdomain>”, as well as similar tracking and image domains so be prepared to edit your DNS. 
-
-2. Ensure that you are able to inject mail using SMTP_Auth with TLS 
-
-  https://docs.kumomta.com/userguide/operation/smtpinjection/?h=smtp_auth 
-
-    NOTE: TLS is crucial to this process, so have a valid and tested certificate attached to your listener config. https://docs.kumomta.com/reference/kumo/start_esmtp_listener/#tls_certificate  
-
- 
-
-## Get Ongage 
-
-3. Go to Ongage.com and create an account https://www.ongage.com/registration 
-
-4. Create a support ticket to request access to use the “Private SMTP” connector and let them know you are using KumoMTA as the sending MTA. 
-
-Here is some essential reading before you set up the Private SMTP connector: 
-https://ongage.atlassian.net/wiki/spaces/HELP/pages/657817611/The+Ongage+Private+SMTP+Connector  
-
-5. Once registered, you can add a vendor by selecting Vendors > My Connections in the left menu 
-
- 
-
-6. Create a new connection and add “Private SMTP” as the connection type. 
-
-     NOTE: If you do not see this as an option, jump back up to step 4 and ask Ongage Support to add it for you. 
-
-7. Fill in all the required fields and test. 
-
-* you can choose any username and password you like, KumoMTA has no preset or preference. 
-
-* Select PLAIN authentication Type 
-
-* Select YES for “Use TLS” 
-
-* The SMTP Port should match what your listener is listening on.  Remember to update your public firewall too.  
-
-If you have done everything right, you will see a positive notification that credentials were verified. 
-
-8. Pat yourself on the back then start using Ongage with KumoMTA 
-
- 
-

docs/tutorial/integrations.md

@@ -1,7 +0,0 @@
-# Approved Integrations
-
-## Hashicorp Vault
-
-## Ongage
-
-