nodejs error

Hello friends, I am developing a site with a nodejs project and I want it to check the username. It does this successfully, but it cannot find the id in my .ejs extension file and does not show me a dynamic error message. Code: const existingUser = await User.findOne({ $or: [ { kullaniciAdi }, { telefon }, { email }, { tcKimlik }, ] }); if (existingUser) { // Eğer hata varsa, hata mesajını içeren bir HTML yanıtı gönderin return res.status(400).send("hatamesaji"); } What I want is to show an error message next to the input in my .ejs extension file instead of the error message here. I want the error message to go away when the user deletes it, such as "the username has already been taken", how can I do it?