After deploying some sharepoint lists using Group Policy via Microsoft Outlook 2016/Account Settings/SharePoint Lists
The Lists would not add unless the user had clicked Allow to this error :
Do you want to allow this website to open a program on your computer?
Program: Microsoft Outlook
This error can stopped being displayed by deploying the below reg key :
Add Key stssync
In that Key Create a Dword : “WarnOnOpen”
For this to apply to All users on the machine apply to the Key’s below