If you are using the free versions or lower plans of an e-mail provider, there is a chance that your e-mails will go to SPAM. This is because the IP used by the provider to send your e-mails have been shared with other free users who might have been marked by many people as Spam and that reputation is carry forwarded to you because of the same IP.
To tackle this, almost all e-mail providers give you the option of getting a dedicated IP(some provide free dedicated IP with costlier plans).
This way you start from scratch and messages go to the inbox and would be spam for the users who have marked it so. Keep in mind that this doesn't make your e-mails immune to spam filters, if too many people mark you as spam, it would backfire.