Dear EaungfahJ,
BookLibary Component for send email use mail functions and configure from Joomla Global setting.
Please try send any email from Joomla, test email with help mass mail function.
Follow below documentation:
docs.joomla.org/Help36:Users_Mass_Mail_Users
First of all you need configure Joomla mail settings.
Log into your Joomla Dashboard.
In the top menu, hover over Site and then click Global Configuration.
Click the Server tab.
Under Mail Settings, configure the following settings and then click Save: Mailer. ...
If you do that and still will have problems, give us
full FTP and admin access
and our team will try to find solution special for You, FTP and admin access You can send to our contact form.
ordasoft.com/contact-us-form
Link on website
Joomla Admin
username
password
FTP
FTP host
FTP username
FTP password
Thanks,
Taras
OrdaSoft team.