After stuffing around all day, I finally worked it out!
I tried gmail and outlook but the email won't send to Kindle.
Outlook error 'basic authorisation is disabled'.
Gmail error 'application-specific password requiried'
I used my ISP SMTP server and it's working now. I can see the HIGHTLIGHTS on my Android devices and PC
You also need to add your email address (SMTP) to 'Approved Personal Document E-mail List' under 'Personal Document Settings' or it won't work.
https://www.amazon.com/hz/mycd/prefe...ttings/payment
Check your email for your Amazon account and approve the 'verify request'.
You can see it processing which takes about 5 minutes in total at
https://www.amazon.com/sendtokindle
You can also manually add ebooks to this web address as well.