Microsoft has announced and delivered a tool to help in the Exchange Hybrid Configuration troubleshooting process.
As you may know, the Exchange Hybrid Configuration allows a simple way to move mailboxes between on premises Exchange and online, share the free/busy details between online and on premises, mail flow security with antispam/antimalware (if going through Exchange Online)….
The process to implement such hybrid configuration has been well improved with Exchange 2013 but there was something missing here to help if something was going wrong during the configuration steps (error messages too vague, difficulties to understand the log files…)
So, the Exchange team has worked hard and now this troubleshooting tool is available.
To run the tool, just go to http://aka.ms/HCWCheck from the Exchange server on which the HCW (Hybrid Configuration Wizard) failed and follow it.
Keep in mind this is a first version of such tool and also a first step in the HCW troubleshooting; more has to come such as troubleshooting for free/busy or OAuth issues (maybe one very difficult to troubleshoot and solve 
)
If you want to share feedback or ask for more feature, feel free to reach the team at HCWCheckFeedback@microsoft.com
When you start the troubleshooting tool, the first thing is to be authenticated to your Office 365 tenant
Then you can start running the tool to check what is happening
It will then download and run a small applet
As part of the verification process, the tool checks your internet domain configuration, certificates settings and services assignment or the federation configuration or Exchange web services web site
It may takes several minutes to complete
And then, once completed, it provides you a results report with the issue(s) found
As you can see, it goes very deeper as it found on my server an issue with the power plan currently set – it is not set to High performance; ok this one may not be a big deal but anyway 
You even have (when available) a link on the right to help you solving the issue found (which open the related KB article), run the tool again or even (if the issue still persist or is not covered by the tool) to open a service request (which redirect you to the service request page on your Office 365 administration page)
