Send books from Calibre.app to Kindle Paperwhite and Kindle apps

Create GMX email account

1. Create an email account on www.gmx.com
2. Open "Settings" and check "Enable access to this account via POP3 and IMAP"

Add GMX email to Calibre.app Preferences

1. Open "Preferences"
2. Open "Sharing books by email"
3. Click "Use GMX"
4. Add GMX credentials

Add Kindle email to Calibre.app Preferences

1. Open Kindle "All Settings"
2. Click "My Account"
3. Copy "Sent-to-Kindle Email"
4. Open Calibre.app "Preferences"
5. Open "Sharing books by email"
6. Click "Add email"
7. Add Kindle Email

Add GMX email to Kindle approved list

1. Go to www.amazon.com/myk
2. Click "Preferences" tab
3. Click "Personal Document Settings"
4. Add GMX email to "Approved Personal Document E-mail List"

Send a book

1. Open Calibre.app
2. Right click on a book
3. Select "Connect/share"
4. Select "Email to..."
5. Select your Kindle email