Run time error on executing the exe manually

I have a Qt application, which runs fine when I execute it from Qt Creator. However, on running it by manually clicking the generated exe, I get the following error :

I would understand if it would ask for missing DDLs (which I could then place in the same folder). But how should I proceed to handle this (in general) ?

P.S. It is not giving any line number in my source code which I could try testing this assert for. I tried using the release mode as well, but the same error.

My qml files were not getting deployed properly and thus this error (this assert is probably on the variable storing the main qml file name, i.e. it should not be an empty string, which in case of missing main.qml, it was). Placing the qml files at correct paths solved the issue.

Also, as @mitch has pointed out in his answer, use windeployqt to find out the dependencies. Although, I have also realized that it doesn't cover all the dependencies (MSVC runtimes for example and other compiler related files sometimes). In that case run the dependency walker and place the missing files manually along with the exe.