CLion fails to find header files in path

I have a project with this structure:

root
|-- src
    |-- phys
        |-- common
            |-- common.hpp
            |-- ...
        |-- ...
    |-- ...
|-- tests
    |-- client.cpp
    |-- ...

client.cpp has:

#include <set>
#include "phys/common/common.hpp"

to which CLion emits errors:

'set' file not found
'phys/common/common.hpp' file not found

Regarding set, I also have "#include <set>" inside files in src, e.g., src/phys/common/common.hpp, where CLion detects it well and allows autocompletion, etc.

Regarding the second error ('phys/common/common.hpp' file not found), here's what puzzles me: In client.cpp I use classes declared in common.hpp, and CLion doesn't detect them but suggests fixes in the context actions in the vain of:
"Import class Foo from ../src/phys/common/common.hpp ?"

needless to say the project compiles well.

What am I doing wrong?

CMakeLists.txt has:

include_directories(src tests utils ...)