You can use SendGrid as an alternate email service that YayPay supports. 

SendGrid is a 3rd party email subscription/delivery service that offers Scalability and pre-defined Deliverability metrics if you wish to partner with this email service provider (SendGrid has its own plans and billing arrangements).

You will need to first sign up for a SendGrid account to connect the service to your designated Email server, and then configure it in YayPay, as illustrated below.

Choose "SendGrid" from the drop-down list:

Once these parameters are configured and the connectivity tested, YayPay will use the above configuration to send emails through the email server. 

The Reply to field can be populated with an e-mail address if you want to be able to receive replies from your recipients. 

Customer custom field with from email/name for SendGrid:

If you have a few sub-companies within 1 YayPay business account and you want their customers to receive correspondence from their dedicated e-mail address and names, there is an option to set up a custom field as a source for Email Sender for your customers.

When you populate these fields (or at least the Email field), the system doesn't use From and Sender Name fields when generating an email, it uses Customer custom fields correspondingly.