Passing skill certification can be a difficult thing to achieve at times. This is especially true if creating a skill for a new device such as the Echo Show.
The Amazon developer blog has released an article that gives some hints and tips on the common pitfalls that they have seen when people are trying to become certificated.
If you are developing an Echo Show skill the blog post is a must read. Failing certification can be a frustrating time, following the guidelines will help reduce the possibility of rejection.