First, we need to enable your Gmail account to receive connections from external programs.
Open your browser and access your Gmail account.
In our example, the following URL was entered in the Browser:
On the login screen, enter your Gmail username and password.
After the login, you need to access the following URL:
Enable the two step verification on this account.
After enabling the two step verification, you need to access the following URL:
Create an application password.
Select the Gmail application and the type of device: Other.
In our example, we named the device pfSense.
Click on the Generate button and take note of the randomly generated password.
Next, you need to access the following URL:
Click on the Continue button to enable external access to your Google account.
Now, you need to configure the pfSense email notification feature.