Why my manually generated mnemonic seed phrase is not recognised by metamask or trust wallet

Question

I created a random entropy using this code

func randomNumGenerator() []byte {

    n := 16
    randomByte := make([]byte, n)
    _, err := rand.Read(randomByte)
    if err != nil {
        panic(err)
    }

    return randomByte
}

And created a checksum

func checkSum(entropy *string) {

    data := *entropy
    checkSumLength := len(*entropy) / 32

    //Sha256 of entropy
    hash := sha256.Sum256([]byte(data))
    // hexFormat := hex.EncodeToString(hash[:])

    bitHash := byteToBit(hash[:])
    *entropy = *entropy + bitHash[0:checkSumLength]

}

And added that to the end of the entropy and divided that entropy into 11 bits equal parts and matched it with the 2048 word list and I got words

"sustain resemble shift future stone merge antique denial devote century clay chalk"

But when I use this words in trust wallet it's showing invalid seed phrase

Can anyone explain me why? I followed all BIP39 procedures correctly in my code