Blazor.SubtleCrypto Decrypting on .net 6

As per https://www.nuget.org/packages/Blazor.SubtleCrypto The package uses SubtleCrypto encrypt/decrypt methods and AES-GCM algorithm and returned in ciphertext. I am under the impression that using a shared key used during encryption, I should be able to decrypt the ciphertext in the backend using System.Security.Cryptography. But I encounter an exception: System.Security.Cryptography.CryptographicException : The computed authentication tag did not match the input authentication tag.

    private static string Decrypt(string cypherText)
    {
        // convert from base64 to raw bytes spans
        var encryptedData = Convert.FromBase64String(cypherText).AsSpan();
        var key = Convert.FromBase64String("V4iOXGCoPpX3UncQ5W9bsfUCqIlWvewbMsBNT4IHZRQ=").AsSpan();

        // 128 bit encryption / 8 bit = 16 bytes
        var tagSizeBytes = 16;
        var ivSizeBytes = 12; // 12 bytes iv

        // cipher text size is whole data - iv - tag
        var cipherSize = encryptedData.Length - tagSizeBytes - ivSizeBytes;

        // extract iv (nonce) 12 bytes prefix
        var iv = encryptedData.Slice(0, ivSizeBytes);

        // followed by the real cipher text
        var cipherBytes = encryptedData.Slice(ivSizeBytes, cipherSize);

        // followed by the tag (trailer)
        var tagStart = ivSizeBytes + cipherSize;
        var tag = encryptedData.Slice(tagStart);

        // now that we have all the parts, the decryption
        Span<byte> plainBytes = cipherSize < 1024
            ? stackalloc byte[cipherSize]
            : new byte[cipherSize];

        using var aes = new AesGcm(key);
        aes.Decrypt(iv, cipherBytes, tag, plainBytes);
        return Encoding.UTF8.GetString(plainBytes);
    }