While X1 "supports" Sharepoint, it is older versions. The current implementation, even when selecting Sharepoint365, continues to use the old and deprecated _vti_bin/search.asmx. This was replaced in 2015 with standardized REST calls. Why haven't these been implemented?
https://msdn.microsoft.com/en-us/librar ... 63876.aspx
After opening several tickets about this, as we usually do, we found the solution on our own.