Official WhatsApp App Keeps Showing Error On My Infinix Smart 8

I am using an Infinix Smart 8 phone with the number +2547481778** as my official line, and for the past few days I have been unable to use WhatsApp at all. The problem started after I erased everything on my phone and tried to set it up again. Since then, whenever I install WhatsApp, it keeps saying that I have not downloaded the official WhatsApp application, even though I downloaded it directly from your official website. Because of this, I cannot use WhatsApp on my device and it is causing serious inconvenience, as this is my main communication line. I have not yet received any help regarding this issue. I kindly request a permanent solution so that I can install and use the official WhatsApp application normally on my Infinix Smart 8 without any error messages, and so that my number +2547481778** can be used again without problems.