Everyone loves Gmail! It's easy and very popular. Well, not really for the production server integration to be honest. Gmail does provide an SMTP integration feature, but there are some many limitations. That being said, for testing purposes its useful and it is free to use.
First of all, you should allow the 'Less secure apps' on your Google account. Google is marking the SMTP access as "insecure" based on their policy, so this is required to make your account for the SMTP emailing.
You could enable it here in Google's Less secure app access section.
If you are using a 2FA, you might need to go through one more step. Google asks you to generate an "App Password" in order to use a less secure app. Which is like a temporary password only for your less secure app access.
You can make an app password here. Make sure to memo the password coming from Google somewhere. This is required on the HollaEx Kit Email Configuration.
The configuration will be similar to the screenshot above.
Now, you'll get emails from your exchange with your Gmail account. Unfortunately, Google only allows 100 emails per day with SMTP. Which is not enough at all for serious production exchanges. We recommend you to look for a proper SMTP email provider such as AWS SES or Mailgun for production use.