why is BmeSensor.h not found when it’s in the project structure? Furthemore, the error occurs only after adding #include "BmeSensor.h to another header (not the one that threw the error).
Hard to answer with just a screenshot.
It looks like that BmeSensor is a private library located in the projects lib folder. And it seems that another private library “Mqtt” tries to include the BmeSensor library…
Is the complete project available somewhere, e.g. via github for a more detailed analysis?