This morning Thunderbird stopped sending e-mails with a JPG or BMP embedded or attached either to myself for other recipients. The "Sending Message" window shows "Status: Delivering mail..." and the "Progress:" bar stalls at 99%. Then in about 30 seconds a "Send Message Error:" box pops up with "Sending of message failed. The message could not be sent because the connection to Outgoing server (SMTP) mail.tlcox.net timed out. Try again." Remove the image and it works just fine. O/S is Windows 10 Pro. Network Solutions is the ISP. Have tried reducing the image size, turning off Kaspersky Total Security malware checker, rebooting the computer and Thunderbird many times. No update was applied between yesterday and this morning to anything.