There are a few settings that need to be configured to allow your G Suite and Gmail accounts for email sending.
First, your security settings must be configured at the domain level in Google Admin Console to enable individuals to set the proper settings.
Second, your account settings must be configured on the individual level in Google My Account to enable access.
The two main settings we need to change are 1. Allowing Less Secure Apps, and 2. Disabling 2-Step Authentication.
1. Navigate to admin.google.com and login to your domain.
LESS SECURE APPS
2. Go to Security > Less Secure Apps: https://admin.google.com/ac/security/lsa
3. Select ‘Allow users to manage their access to less secure apps’ > Save
4. Go to Security > 2-Step Verification: https://admin.google.com/ac/security/2sv
5. Set Enforcement to Off > Save
Google My Account
6. Go to https://myaccount.google.com/security and login to your Google account
7. Scroll to Signing in to Google > 2-Step Verification > Set to Off
8. Less Secure app access > Turn on access
Still getting blocked? You may need to do a Captcha Unlock
Visit https://accounts.google.com/DisplayUnlockCaptcha and sign in with the Gmail username and password.
If necessary (it’s usually not), enter the letters in the distorted picture then press Continue.
This will allow for ten minutes for the 3rd party account to register as an approved connection. Note that you must use the account you are trying to add to the 3rd party account – if the browser is already signed into another account, you must sign out first.
Alert us as soon as this step is complete, as we will have 10 minutes to connect your account to our system.