Why can I only use one Xiaomi dual card?

Demonstration model: Xiaomi 1 1 System version: MIUI 12.5.6 Only one Xiaomi dual card can be used. Maybe another card is not put away properly, and the mobile phone can't recognize it, or the card slot is broken and needs to be repaired in a specialty store. Using GSM dual-card dual-standby mobile phone, two GSM network mobile phone numbers can be used on one mobile phone at the same time, and the two cards can be switched at will when calling the Internet.

Xiaomi:

It is a global mobile internet enterprise focusing on the research and development of intelligent hardware and electronic products, and also an innovative technology enterprise focusing on the construction of high-end smart phones, Internet TV and smart home ecological chain. Xiaomi Company pioneered the development of mobile phone operating system in Internet mode, and enthusiasts participated in the development and improvement mode. Living for a fever is Xiaomi's product concept. It is Xiaomi's vision to let everyone enjoy the fun of science and technology. Xiaomi Company applies Internet development mode to develop products, makes products with geek spirit, and kills intermediate links with Internet mode, so as to make everyone in the world enjoy high-quality scientific and technological products from China.