Less does not finish compiling
We have been seeing in some cases the compile to less behaviour timing out in some of our zgfv4 themes.
The error can be caused by a number of different factors but generally it's to do with inadequate server resources, an error in the less file or a security protocol that limits the ajax functionality in our templates.
Using Admintools Pro
Using Admintools Pro and it's blocking the scripts. Read this article.
Execution time too low
Your servers execution time isn't high enough to allow for the processing of the Less. See how to increase the server execution time.
Server memory tool low
Your server memory isn't high enough to allow you to process the less. Learn how to increase the server memory.
Error in .less file
There is an error in one of the less variables. You may need to look in the inspector to see this.
Site is offline
Your site is currently offline. If your site is offline then you will need to open a new tab for your website and login to the front end of the website.
We have been building in better warnings and guides regarding this in the templates - more coming in v1.3. But for now this post should stand as a guide for helping trouble shoot the issues.