Why does sending account activation email from Codeigniter 3 fail?

Print the error message:
https://www.codeigniter.com/user_guide/l...t_debugger

You are specifying smtp settings but sending with mail. Change protocol into smtp.
You can also delete mailpath and smtp_timeout (sometimes servers hate a too high value).
You need to specify smtp_crypto, due to the fact you are using a ssl port.