Is the internet connection working? 

Check the queue tab to see if there are emails  waiting to be sent. 

Are you using Send Grid or SMTP? 

1. Sendgrid    
1. Verify username and password are correct.  Go to sendgrid.com and log in instead of just saying yes.     
2. Verify there are only Latin characters and the  message is under 600 characters.  
2. SMTP
1. Verify email credentials are correct with email  provider.
2. Some SMTP connections require the from email and  the user email to be the same. 

 

Are the windows firewalls and any 3rd  party security programs disabled? 

Is the internet connection set to home or work  instead of public?   

1. To change, go to control panel > network and  sharing center.  Click on connection type  and choose another connection.