...
Go to Gmail Settings by clicking on the “Manage your Google Account“ option.
Search for App Password Manager in the search bar and click on it. The app Password page opens.
Click on the Select App option and select Other(Custom Name) in the dropdown.
Give any Custom Name and then click on the Generate button to generate the password. Copy this password as it is used in configuring the SMTP profile.
Log in to your Jira/Confluence instance and go to the system settings.
Click on the Outgoing Mail in the left menu bar and click on Configure new SMTP mail server button to configure the SMTP profile.
Provide Gmail id as the username along with the other necessary details as shown in the below screenshot and provide the password you have generated in the App password section. Then click on the Test Connection button.
Once the connection is successful, then click on the Save and Authorize button to save the connection.
Your profile is created.
To test the SMTP profile click on the Send a test email button and provide the required details. Click on the Send button to trigger the email.
Check your inbox for the confirmation email.
...