Customer typically fails to receive email notification from us because of many reasons, most commonly are network disturbances and/or customer’s mailbox is full. You can rely on to that reason, if it happens to one or some of your customers.
There is no restriction against email domain in order to receive our email notification.
If it happens to all of your customers, please make sure you already enable the feature ("send email to customer") through your Midtrans' portal.
There is another possibility regarding this issue, please make sure that email alias (email support) that being set on your Midtrans' portal not using yahoo domain. Email support will be used as an email sender in email notification to your customer, and there is DMARC policy from yahoo that will reject the email if it using their domain.
More details please click here.