Fatal error LNK1120 when separating code into .h and .cpp files

Question

I'm trying to code Matrices in C++, and weirdly enough, although everything was compiling fine; the moment i added a new constructor that takes a 2D array by ref, my build started always failing with this error:

1>Main.obj : error LNK2019: unresolved external symbol "public: __thiscall Matrix::Matrix<4,2>(double (&)[4][2])" (??$?0$03$01@Matrix@@QAE@AAY131N@Z) referenced in function _main
1>C:\Redacted\For\Privacy\Reasons\Matrix.exe : fatal error LNK1120: 1 unresolved externals

I tried compiling the code in a single file and it works fine : https://techiedelight.com/compiler/?IQe2

The only code i have right now is in 3 different files, Main.cpp, Matrix.cpp and Matrix.h which are as follows:

// Main.cpp
#include "Matrix.h"

int main(char* args) {
    double data[4][2] = {
        {1,2},
        {3,4},
        {5,6},
        {7,8}
    };
    Matrix* matrix = new Matrix(data);
    std::cout << matrix->toString() << std::endl;
    delete matrix;
}

// Matrix.cpp
#include "Matrix.h"

template<int r, int c>
Matrix::Matrix(double (&matrix)[r][c]) : ROW_DIM(r), COL_DIM(c), ELEMENTS_COUNT(r * c) {
    data = new double[ROW_DIM * COL_DIM];
    for (int x = 0; x < ROW_DIM; x++)
        for (int y = 0; y < COL_DIM; y++)
            data[x * COL_DIM + y] = matrix[x][y];
}

std::string Matrix::toString() {
    std::string result = "";
    for (int i = 0; i < ELEMENTS_COUNT; i++)
        result.append(std::to_string(*(data + i)))
            .append((i+1) % COL_DIM == 0 ? "\n" : " ");
    return result;
}

#ifndef MATRIX_H
#define MATRIX_H

#include <iostream>
#include <string>

class Matrix
{
public:
    template<int r, int c>
    Matrix(double (&data)[r][c]);

    std::string toString();
private:
    const int ROW_DIM, COL_DIM, ELEMENTS_COUNT;
    double* data;
};

#endif

I've been banging my head at this for 4h and I googled fatal error LNK1120 but all were unrelated to my specific case. Any ideas or help is greatly appreciated