I have stopped using yahoo, so I am not well placed to help you. But I read here and in other places that yahoo have been changing their authentication systems. I doubt that you can easily use the simple smtp set-up on an IP camera with these systems. If it's OAuth2, you generally have to visit a web page to identify yourself. If yahoo offer it, an "application-specific password" may work for you. I use an IP camera and a video server myself and have similar issues. I needed to try the various smtp servers available to me. Some worked for a while but became useless because the operator decided that the high volume of messages could only be spam. It's hard to get past the first level of support to talk to someone who can help, and often they won't be keen on setting up an exception. I have also found, increasingly, that it's hard to find a web browser that can now connect to an IP camera's web server, due to the closing down of utilities such as activex controls and flash. If I were to go out to buy an IP camera today, I'd be looking for java applet technology, since this seems to be most likely to be supported in a modern browser. Ultimately I found that my domain registrar's smtp server was most tolerant and allowed my IP camera and server to send images via email. I wouldn't expect to get yahoo to do this. Is email your only option? I have found that running an ftp server which the camera can send its images to is a useful backup for when the SD card becomes full. Most of these cameras seem to have flaky firmware that doesn't so what it offers. They have options to delete old messages when the local storage is full, but mine fail to actually do this.