Configuring Grandstream IPPBX UCM’s Email Setting (Gmail)

Grandstream UCM Email Setting Feature Image


This article shows you the steps by steps on how to configure and troubleshoot Grandstream UCM’s Email Setting using a Gmail account.


  1. The Grandstream UCM uses SMTP to send out the emails. Configure SMTP Server to Each time you make changes to the Email Setting, you have to re-enter the email authentication password otherwise, the UCM saves garbage. 
Grandstream UCM Email setting
Figure 1: select Client type and enter Gmail SMTP Server:

2. Go to PBX Settings –> Network Settings –> Basic Settings > DNS Server 1, enter Google DNS (for eg., followed by Save and Apply.

Grandstream UCM Email setting
Figure 2: Enter DNS Server 1:

3. Log in to your Google Account > Security > turn on 2-step Verification and App Password. More details can be found here. If you see no app-specific password when you visit this page:,

Figure 3: Enable 2-step Verification and App Password under Google account > Security
Figure 4 Select Other (Custom name) under Google App Passwords
Figure 5 Name the App and click Generate to create the 16 digits password
Figure 6 Copy this 16-digit Google App Password to UCM Email Setting > Password

4. Go back to the Email Setting page, make a test email, and verify if the emails go through under Email Send Log tab

Figure 7: Verify the Send Result and Return Code of the test emails


Go to Maintenance > Network Troubleshooting > select the Interface and click Start to run Ethernet packet.

Grandstream UCM Email setting
Grandstream UCM Email setting
Figure 8: You will see the traffic of SMTP and DNS sent to/from UCM (IP: when sending emails.
Figure 9 Syslog shows 200 OK that indicates the email test is sent successfully.


  • Please remember that certain email servers might consider emails coming from MTA as spam.
  • Reboot the UCM each time you change the Mail type (Client/MTA)