If you have Outlook 2016 (or others) installed on a Windows 2019 server, when you click a Hyperlink in an email message you may received the error:

When clicking on a hyperlink in Outlook, this warning appears. Your organization's policies are preventing us from completing this action for you.

To resolve this issue please install the hotfix (designed for Windows 10), available here:
https://support.microsoft.com/en-gb/help/310049/hyperlinks-are-not-working-in-outlook
Hotfix name: MicrosoftEasyFix50388.msi

To get the hotfix to run on Windows server 2019 use the compatibility troubleshooter (otherwise it doesn't run for 2019).

Ensure you are logged in as administrator. Once run it works fine for all users (HKEY Class registry update with missing html classes).