I installed web essentials 2017 after downloading it from the Marketplace Link-https://marketplace.visualstudio.com/items?itemName=MadsKristensen.WebExtensionPack2017 . Then installed it after closing Visual studio and tried ZenCoding in a razor page. puffff tab doesn't work.
I don't have ReSharper
After going through a lot of blogs, a few suggested the same solution, that we need to follow the installation steps
Then try ZenCoding, if it doesn't work uninstall both i.e. Web Essentials & ZenCoding and follow set 1 & 2.
This worked for me.