As you know Nowcerts sends a lot of emails on your behalf (certificates, documents, forms, etc) through your emails accounts via SMTP.
These kinds of emails can often be interpreted as Spam or even hacks by receiving email servers.
Recently there has been a push in the industry to deal with the problem of separating "Real" emails from Spam. http://www.openspf.org/
As a result, you may see an increased number of undelivered emails, so-called Bounce-backs.
Luckily, there is a simple solution. Here are the instructions to get rid of bounce-backs.
You need to contact your email administrator and ask them to add the following TXT/SPF records to your DNS Zone file. This is what your SPF record needs to look like:
put this in the TXT field:
This is NOT something thatmust be done, but it we highly recommend it, especially if you are getting bounce-backs or emails from Nowcerts are going to spam.
This will help ensure that all your emails from Nowcerts get delivered.
SPF Builder wizard: https://www.spfwizard.net/
MX record look up: https://mxtoolbox.com/SuperTool.aspx