There was a bug in the requester that made it throw a TimeoutException when the real cause of the problem was a different error. The fix for this issue makes the requester throw an exception with the real error.
In the proxy config of the description, the "Remotely closed" error caused when trying to connect to Tomcat made the requester throw a TimeoutException. The cause of this problem is an issue with the keepAlive in the requester. A new JIRA has been filed to track this: MULE-8603.
For the other problems described in the comments, you can test again with this fix to check whether the cause is really a timeout or a different issue.