You are free to send any number of messages, including newsletters, as long as you remain within your sending limits.
However, sending a large volume of messages (mass mailing) or unsolicited emails is regarded as spam.
These, along with any other spam-like behaviors are not allowed according to our Terms of Service.
If bulk mailing is crucial for you, you may consider a specialized service, such as MailChimp, MailGun, UniSender, Omnisend, and other email marketing solutions.
Find out more about Email limits here:
https://my.hostking.host/knowledgebase/201204815/Limits-of-Hostking-Email.html
