If you have a G Suite account and are trying to use that account to send emails through Kennel Connection, you cannot have 2-Step Verification enabled as it will not work. Please see below on how to disable it. 

Part 1. Admin Settings:

First you must login to your G Suite admin portal. Open a web browser and navigate to https://admin.google.com 

Login with your G Suite admin ID and password. This is an email address and password and usually the one you used to signup for G Suite. 

Once inside, click on the hamburger menu in the upper left.

Move your mouse over SECURITY and then choose SETTINGS. 

Find and click on the "2-Step Verification" option. 

While there are many options in here, we're only focusing on the main option. For more in-depth assistance on other options, please contact G Suite support. 

Here you can either uncheck the "Allow users to turn on 2-Step Verification" which will remove the option from the inboxes of all your users accounts OR you can set the enforcement to OFF which means you don't require it to be turned on and it lets it be enabled or disabled inside each mailbox. 

Choose your setting and then click SAVE in the lower right hand corner. 

You may now close out of the admin portal. 

Part 2. Gmail Inbox Settings:

Now you must login to your G Suite email inbox. Once logged in, click the G Suite button in the upper right hand corner and choose "Manage your Google Account"

Once inside the account settings, click on the security option on the left hand side:

Look for the 2-Step Verification setting. If it shows ON, you must click it and turn it off. If it shows OFF, you can close out of Gmail inbox as you are all set. 

Changes will save automatically.