Like a lot of others I have found just recently that  when I add photos to an email in Windows Live Mail - they don't go out of the Outbox and I get an error message.  This applies if I use photo album or insert single photo or even if I just add the image file as an attachment.  I've read some of advice on this forum and tried a few things including running a fix on Widows Essentials but that didn't work. 

I am running Windows 10 on a laptop and I have a back up laptop.  I just checked it and I found the same problem.

The error message is 

Server   "mail:btinternet.com"

Windows Live Mail Error Code ID: 0x8007007A

Protocol: STMP

Port: 25

Secure (SSL):No

I tried changing No to  Yes in above but that did not help

Regards

Allan Jones