Could not load libfieldFunctionObjects.so and user created library

Hi,

I have created a user defined object using the wmake in OPENFOAM 20.06. The in Make the files contained the following: Helicity.C

LIB = $(FOAM_USER_LIBBIN)/helicity

Therefore, the new created object was helicity.so.

I included both helicity.so and libfieldFunctionObjects.so in controldict. However,

when running interphaseChangeFoam I am getting the following:

--> FOAM Warning :
    From void* Foam::dlLibraryTable::openLibrary(const Foam::fileName&, bool)
    in file db/dynamicLibrary/dlLibraryTable/dlLibraryTable.C at line 65
    Could not load "libfieldFunctionObjects.so"
/home/ncharala/OpenFOAMv2006/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libfieldFunctionObjects.so: undefined symbol: _ZTIN4Foam15functionObjects15fieldExpressionE
--> FOAM Warning :
    From void* Foam::dlLibraryTable::openLibrary(const Foam::fileName&, bool)
    in file db/dynamicLibrary/dlLibraryTable/dlLibraryTable.C at line 65
    Could not load "helicity.so"

How can I fix this?

Thank you Nicolas