What does it mean to send a message to check the security code and reply null?

It may be a system error or it may not be found. If you check it on the website, if the purchase channel is formal, you don't have to worry about authenticity.

Anti-counterfeiting codes are generally composed of numbers and letters, which are usually located on the packaging and coated. The serial numbers of some electronic products can also be used as anti-counterfeiting codes (the packaging is invisible unless it is damaged and must be hidden). If the coating of the security code cannot be scraped off, it is likely to be a forged security code or a counterfeit product. You can go to official website to inquire about the product (you can see the inquiry record). If the displayed security code has been inquired or cannot be inquired, the purchased goods are not genuine.

If the purchased product has an anti-counterfeiting code, you can inquire according to the phone number and website prompted by the product. If it can be found and displayed as the first query, it is genuine. There are generally four ways to query the security code: telephone inquiry, SMS inquiry, website inquiry and manual service desk. Generally, it is the most intuitive and quick to inquire about products in official website, which is recommended. If you can't find the security code information, it means that the product is probably a counterfeit product, or it may be a system problem (you need to find a manual service desk to confirm).

If the product does not have an anti-counterfeiting code, it is not completely certain that the product is a counterfeit product. Generally, the old batch of products may not contain anti-counterfeiting code, so you need to check the announcement in official website or call the official manual service desk for confirmation. If the appearance and packaging of the same product are exactly the same, and the genuine product has an anti-counterfeiting code, but the customer does not have an anti-counterfeiting code when purchasing it, it is generally a counterfeit product.