There are various reasons for failures, and sometimes resolving one issue leads to the emergence of another. Microsoft aims to help administrators in understanding these issues better by collecting end-user diagnostics and presenting them in a new tool called the "Best Practice Configuration Dashboard."
In my opinion, this tool will not solve all your problems, and you will still need to identify where in the network the issues may lie. However, it will provide a better understanding of some of the most basic issues. The Dashboard currently offers insights into client versioning (suggesting updates), explains which ports are being blocked for end-users (causing failures or reduced quality and functionality), and detects if VPNs are in use, suggesting split tunneling where appropriate.
This feature is mentioned in Roadmap ID 421185 and is expected to roll out at the end of this month and onward.