Answer
This might be down to one of the following:
- Your e-mail address is written incorrectly.
- The e-mail is in one of the following folders in your e-mail account: "Spam", "Junk" or "Social".
- Your inbox is full so you can’t receive any new e-mails
- You’ve placed e-mails from XING on your blacklist with your e-mail provider.