How to determine what is causing Application error 0xc000007b?

I have an application that is working very well on my computer. On the other hand, after releasing it, someone reported it is having error 0xc000007b.

My application is build using Visual Studio 2015, and has both x64 and x32 builds.

What is the best way to answer him, when I do not know what Operating System he is using?

How can I ask him to track this issue he has, when he is the only one reporting this error?