Why can't the mobile phone receive the verification code of Wal-Mart's non-cloud ring communication?

Due to network delay and server communication delay, the mobile phone can't receive the verification code of Wal-Mart Feiyun system, which leads to the inability to receive short messages. According to relevant public information, today's smart phones have great advantages over previous mobile phones, and can intercept a large number of spam messages. Smart phones can't identify the message content well, and the mobile phone housekeeper will intercept the verification codes of some platforms. When you receive a verification code email, you will treat it as spam.