There are 4 main factors in deliverability:
When you send an email, the email must have a 'from' email address. As your email is being sent from a server, the server must be allowed to send emails on behalf of the domain in the 'from' email address. The owner of the domain must give explicit permission for any server to send on behalf of that domain. Without this explicit permission, anyone could send emails on behalf of you and no one would be the wiser. The owner of the domain can set up records that define which servers are allowed to send emails on behalf of the domain. The permission is set up either by setting up MX/SPF records on the DNS (Domain Name Server). When your email client server receives an email, it checks the DNS records to see if the server permissions are set up. If they are not, the email is rejected. NOTE: In Enquire MAP, all emails require CNAME records to be set up to register this permission:
To check to see if the permissions are set up correctly, you can review the records in Administration>Account settings>Account Setup section>VIEW WHITELABELING:
If you haven’t set them yet for a new account, follow the steps outlined in this article: https://support.activedemand.com/solution/articles/5000011983-integrating-activedemand-with-your-website-email-server
For the case when your company uses Outlook, you may find the emails that you send internally with Enquire MAP (i.e. testing, etc) end up in your junk folder. Do not be alarmed. It is the case that office 365 requires a bit of extra setup to allow others to send emails with your domain to your company. To ensure the emails are delivered internally, you might need to adjust your SPF records. An SPF record is used to tell the world which servers can be considered as trusted. Using outlook/office 365, you will have had to set up an SPF record to allow Microsoft to send your emails. It is important to note that you can only have one SPF record. Thus if you have one already, you will need to adjust it.
Here is a great tool for adjusting your SPF record: https://www.spfwizard.net/
Also, you should add the Enquire MAP servers to your admin panel in Office365 as trusted.
IPs: 126.96.36.199, 188.8.131.52, 184.108.40.206, 220.127.116.11, 18.104.22.168, 22.214.171.124, 126.96.36.199, 188.8.131.52
If a lot of spam has been sent via your domain, the domain will get a reputation that is less than desirable. One bad actor using your domain can ruin it for everyone in the company. If the actor is bad enough, the domain will be blacklisted and make it very difficult to deliver any business emails.
If the server that you are sending emails from is shared, and others are sending spam, the IP address can get a bad reputation. Note, Enquire MAP uses a reputation based IP pool system. The like actors are migrated to the appropriate pool of servers. Enquire MAP has a low tolerance for bounce/spam. Thus even the worst actors are still great marketers. That being said, those that are top performers are rewarded by being given access to the premium pools. The system is automated, thus there is no way to 'buy' your way into the top tier.
Most email firewalls are very good at determining the type of email being sent. If you send image heavy/html heavy emails, the emails will be flagged as promotional. If you send emails with large dollar amounts and messaging that can be inappropriate in nature, this will be flagged as spam.