You run the Hybrid Configuration Wizard to set up a hybrid deployment between your on-premises Microsoft Exchange Server environment and Exchange Online in Office 365. However, you cannot select a digital certificate because the drop-down list in the wizard is empty.
Additionally, when you try to continue, you receive the following error message:
No valid certificate exists for the Hub Transport server(s).
This issue occurs if the Microsoft Exchange Service Host service on the hybrid server has stopped running.
Start the Microsoft Exchange Service Host service on the hybrid server. To do this, follow these steps:
Click Start, click Run, type services.msc, and then click OK.
In the list of services, right-click Microsoft Exchange Service Host, and then click Start.
Microsoft Exchange Online, Exchange Server 2016 Enterprise Edition, Exchange Server 2016 Standard Edition, Microsoft Exchange Server 2013 Enterprise, Microsoft Exchange Server 2013 Standard, Microsoft Exchange Server 2010 Standard, Microsoft Exchange Server 2010 Enterprise