allowedusernamecharacters code example
Example: c# allowedusernamecharacters
services.AddIdentity<ApplicationUser, IdentityRole>(options => {
options.User.AllowedUserNameCharacters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._@+/ ";
});