When using Exchange 2016 with Windows Server 2016, you may get this issue, when you open OWA:
“ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY”
This is displayed in Google Chrome.
This is due to enabled SSL ciphers that are outdated on IIS, and can be “lock down’ed” with this free utility:
https://www.nartac.com/Products/IISCrypto
Run it on the Exchange server and press “Best Practices” and Apply, reboot the server, and everything is now fixed 