Customers who have fully customized domains configured on their ProofHQ accounts may have spam filters problems, related to SPF not being set, or being set incorrectly.
In order to ensure that all email notifications are always received by you and your reviewers, you should set up an SPF record for your customized domain connected to the ProofHQ account (e.g. proofing.yourdomain.com).
SPF stands for Sender Policy Framework. If you set up an SPF record for ProofHQ on your domain, you are basically telling your domain that you trust ProofHQ to send emails on your behalf.
When ProofHQ sends an email notification to one of your reviewers, it is sent from a ProofHQ email address, e.g. email@example.com (even though the sender name shows as being the person who performed the action in ProofHQ), and if you have an SPF record set up on this URL this means that your recipients' mail servers will see that the emails are from a source that you trust, and so it will be accepted.
To set up an SPF record, you will need to include the SPF record used for our primary domain.
You do this by adding a DNS TXT entry for your domain with the following value:
v=spf1 a:mx.proofhq.com -all
Your email administrator or IT personnel should be able to help you set this up.