Frequently Asked Question
As XACARS is a plugin compiled with older library version of the Windows inveronment you are probably missing some libraries. If you check you X-Plane log the following entry can be found:
D:\XPlane11/Resources/plugins/XACARS/64/win.xpl : Error Code = 126 : The specified module could not be found.
Solution: install the Microsoft Visual C++ 2010 and 2012 Redistributable Packages