Solution for error "ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY" when attempting to access Microsoft Exchange Server 2016 Outlook Web Access.
- Log into Windows Exchange 2016 Server
- Copy link https://www.nartac.com/Products/IISCrypto and download GUI tool
- Click on "Best Practices" button
- You will notice it will uncheck some options
- Click apply and reboot
- Test and confirm Outlook Web Access works again.
Note: After you restart, your server may appear with the exclamation mark, continue with logging in and it should acquire connection.