I tried to do an upgrade of my Exchange2016 server from Cu7 to Cu16. It got all the way thru to and stopped at the "finishing up" stage. I rebooted the server and then checked the version and it looked like everything upgraded to the correct version, but Outlook wouldn't connect. I found an article that told me to do this:
Copied sharedWebConfig.config file from C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy directory.
Pasted sharedWebConfig.config file in C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess directory
Now Outlook connects but it doesn't appear to be sending or receiving emails. Can I run the CU install again?