Settings > Inboxes > Choose an inbox > Email Settings:
You need to select the option to switch from 'Teamwork will send my emails' to 'Send email with custom outgoing (SMTP) settings'.
You can then choose from some predefined providers which will allow you to simply use your login for that service without having to add any other details, or if you choose the 'Custom' option you can add all of your SMTP server details, including the port and whether you'd like to use SSL or TLS security. You may need to whitelist the Teamwork Desk servers in your SMTP server to make sure that it will send the email.
Please note that if you are using your Gmail account, you will need to use an App password when using 2FA or change a setting to allow this.
You can use the 'Test Connection' button to verify your settings and if you're happy to go ahead, use the Save button at the bottom of the screen to apply those changes.
Desk is configured to fallback to using our system to send emails if your SMTP server fails to send any emails.
Whitelist Our ServersTeamwork Desk will connect to your SMTP server from the following IP Addresses: