Sony Xperia Z5 Compact Android 7.0, Contacts not syncing to Outlook

A

AC Question

Hello, I have been using my Sony for about 12 months connected to Outlook (Hotmail). Contacts was syncing my Outlook contacts but all my contacts are now gone and all my messaging is just showing with just mobile numbers.

I have tried uninstalling Outlook Mail app, deleting the account. Reinstalling and recreating the app but still not being synchronised correctly. the sync is up to date with no errors; mail is working fine but for some reason the contacts are not being pulled across.