There are several reasons why your emails could land in the Spam/Junk folder.
First, check is If your CNAME records are set up properly. You can see it 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 ActiveDEMAND (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
Also, you should add the ActiveDEMAND servers to your admin panel in Office365 as trusted.
IPs: 220.127.116.11 18.104.22.168 22.214.171.124
Doing the internal trust for the IPs will make your outlook server happy.