If you are using MS Exchange 2013, 2016 or Office 365 and you are sending mail from Incomaker, it may happen that the mail goes correctly to all recipients except your own domain. This is because MS Exchange, which is set up as your domain administrator, identifies mail from your domain sent from another server as phishing. In other words, if it receives an email from your domain but Exchange itself did not send it, it considers it a scam.
This problem does not affect all recipients, but only you as the domain owner. Ironically, your messages usually arrive normally to others.
There are of course general technologies, such as SPF, that solve this problem, but specifically for MS Exchange this is not enough and needs to be set up separately. Fortunately, this is easy to do.
The setup procedure is described e.g. in this tutorial. Add the following to the list of secure addresses: