Came across a problem with a family member who'd upgraded their Wileyfox Swift to Android 7.x, guessing it's their new version without Cyanogen on the sticker, but had lost all his contacts in the first place. Seems the original OS had the ability to add a Hotmail account and sync all the contacts to it using the built-in mail app, and the new one only had the ability to read it over IMAP. The confusion mainly arose because the hotmail account was also his Google account, and Android was trying (and obviously failing) to sync Gmail.
The solution is to remove the IMAP account from gmail/whatever mail client they have, and install Outlook from the play store, and go into settings and set it to sync contacts. Instant relief.
Hope this helps someone.
