I am using posix_memalign to allocate memory, but when I try to use the vector I get segmentation failure

I created the following function that takes all the elements of the square matrix to a vector of the appropriate size.The function works correctly with malloc, but I need to create the vector with posix_memalign and there the error occurs.

void convert_matrix_to_vector(int **matrix, const int matrixSize, int **vector, int *vectorSize){

    int *vectorAux, i, j, k, vectorSizeAux;

    vectorSizeAux = matrixSize * matrixSize;
    posix_memalign((void **)&vectorAux, vectorSizeAux, vectorSizeAux * sizeof(int));    
    k = 0;
    for (i = 0; i < matrixSize; i++){
        for (j = 0; j < matrixSize; j++){
            vectorAux[k] = matrix[i][j];
            k++;
        }
    }
    free_matrix_memory(matrix, matrixSize);
    *vector = vectorAux;
    *vectorSize = k;
}

When I run the program, the value of vectorSizeAux is 16.

The error that appears is: Program received signal SIGSEGV, Segmentation fault.

When trying to execute the line:

vectorAux[k] = matrix[i][j];