In Reply, you can set up an email account to use different servers for sending and receiving emails. This option is available in the following cases:
When you use mass email systems such as SendGrid or Mailgun
When you use email aliases in Reply
How to set up a connection with Sendgrid:
On the SendGrid side:
Connect your email account to SendGrid.
On the Email API tab, select Integration Guide and then the SMTP Relay option.
Create an API key for sending emails by clicking the Create Key button.
Copy the generated key (you will need it to configure the integration in Reply).
On the Reply side:
In your Reply account, navigate to the Email Accounts tab of the Settings page.
Click the Plus button to add a new email account.
In the Setup email account for sending dialog window, select Other provider and click Continue.
In Account settings, enable the option I want to use different email servers for sending and receiving emails.
In the User name field, enter the email address you want to use to receive replies.
In the IMAP Host field, enter the address of the IMAP server (imap.gmail.com for Gmail accounts).
In the IMAP Port field, enter the port of the IMAP server (993 for Gmail accounts).
Enable the Enable SSL option (for Gmail accounts).
Check the Replies should go to a different email address check box (see the screenshot below).
In the Email field, enter the email you have connected to SendGrid.
Set the User Name to apikey as a standard user name.
In the Reply To field, enter the same email you use in the IMAP User name field. Using this field, Reply knows the email address to receive and detect replies.
In the Sender Name field, enter your name (example on the screenshot below, Reply Team).
In the SMTP Host field, enter smtp.sendgrid.net.
In the SMTP Port field, enter 465 (or 25)
In the Password field, enter the password you copied earlier in your SendGrid account.
Enable the Enable SSL option with the 465 port, and leave it disabled if the port is 25.
Please NOTE that Reply doesn't detect bounces which SendGrid or Mailgun sends to your mailbox. The best way to keep track of bounces would be to:
1 - Export bounces from SendGrid into a CSV file
2 - Import the CSV in Reply
3 - Mark prospects as Bounced, add them to a specified list on the People page, or blacklist (recommended).