At Netwalk we are very serious about your emails deliverability.
Netwalk app uses Sendgrid.com to send transactional emails (books, packages, notifications, etc.) and they do all the heavy lifting for delivering emails but we need you to make sure your SPF record is setup properly:
As we send email on behalf of your email address you need to include Sendgrid smtp servers in the same SPF record of your domain. Below is sample syntax
‘v=spf1 include:[your mail servers] include:sendgrid.net ~all’
For any further info please drop a line to email@example.com