It could be that your sending from email is a public email.
Sending From a Public Domain
If you are sending messages from a free domain like gmail.com56, yahoo.com59, etc., your messages will likely go to the spam folder. You'll want to be sure to send mail from a domain that you own and that matches your branding.
Why emails are going to spam folder?106
We HIGHLY suggest you to get your own domain name and set up an email address using that domain.
You purchased domain name as ABC.COM51
You can create email like yourname@ABC.COM51
Once you have done creating the email using the domain name you purchased, please let us know and we will help you to add it on the system.
Please contact us through chat and we are more than happy to help fix this.