If you are part of an organization like a hospital or an enterprise - and you are trying to improve deliverability and to send emails via Credentially to a large number of people in your organization there are 2 things you will need to do (your Admin IT person will need to do this):

1. Whitelist the Credentially IP addresses with your mail servers:

198.2.177.190

2. Add the Credentially sending domains to your approved senders list:

This will help ensure better deliverability of your emails.

Here is how Google describes this:

An email whitelist is a list of IP addresses from which your users expect to receive legitimate mail. When you add an IP address to your email whitelist, mails sent from this IP address will generally not be marked spam.