Cause 1: Your email settings you entered in KC, Business, Info, Email are incorrect. Please verify with your email provider the proper settings and double check for any typos. If you are using Gmail or Google Workspace, here is an article to use their settings: Gmail/G Suite Email Settings for Kennel Connection
If you use other email providers, check to make sure you're using the right port # and security.
SSL is port 465
TLS is port 587
Port 25 is an unsecure port and in general not accepted by most email servers today.
Cause 2: Your antivirus program is scanning outbound emails.
Disable scanning of outgoing emails. Exclude Kennel Connection from your antivirus program. Click on Antivirus programs and Kennel Connection for directions.
Note that your email provider scans emails before sending to recipients so in most cases having your local anti-virus scan emails is not needed. This decision is up to you if you wish to turn it off or not. However, sometimes adding exceptions isn't enough and with the email scanner component still enabled, emails may not get sent. If this is the case and you wish to NOT disable it, you'll need to contact your anti-virus vendor and let them know and they can provide you a solution.
Cause 3: Your network or internet connection is too slow to send bulk emails.
Verify your connections are solid and fast enough to handle this function. You may need a certified network technician to assist you.
Note that this mostly applies to unstable hotspots, satellite and any dial up connections that may be out there.
Cause 4: The SMTP's server is blocking your connection. Contact your email provider for more assistance if none of the above help.
Many email providers these days do not allow you to use their email servers to send email from third party software such as KC without enabling special settings. If you're using Gmail, you can try the following articles in the order they are listed.
Error "Failed to get response to login password" using Gmail in KC
Error Gmail Still Blocking Account Access After Enabling Less Secure Apps
If using Yahoo or AOL mail, you can try these steps:
AOL/Yahoo Email & Kennel Connection