Reproduction steps:
1. Open the user's attached project;
2. Try to play the main scene.

Actual results: The project crashes without any pop-up Bug Reporter window, yet, if you try to build the project, the build succeeds without any problems, regardless of build target.
Expected results: the build fails too if there is any kind of problem in the editor.

Reproduced on: 2017.1.3p4, 2017.2.2p4, 2017.3.2f1, 2017.4.3f1, 2018.1.0f2, 2018.2.0b3.
Reproduced only with .NET 4.6 version, 3.5 version works as expected.

Won't fix - the bug is on Firebase plugin side, but also fixed in version 4.4.3