email activity

I received so many data errors.

there is server problem or a script problem. People are signing up with fake or false email addresses in order to get on your site to spam it, this is what will be seeing, undeliverable emails.

I need help where can I find to setup email to a person who just submit after signup to avoid these fake email addresses.

You need to go to Settings => Advanced Settings and set it to require a confirmation e-mail upon joining