How to Import Tasks and events

How to Import Tasks and events

Hello,

I'm facing a problem during a migration to import tasks and events from another CRM system (Sugar CRM). In the import field matching page, I have two fields WhoId and WhatId to, apparently, connect the imported task with the related contact and / or account.

If I match the WhatId field with the contact or account id of my previously imported contacts and accounts, it seems to work, but the result is somewhat odd : If I check a contact, I can see the related tasks, and click on them. But once I display this very task, I can't see the related contact or account ... The relation appears to be only one way ...

What am I supposed to place into the WhoId and WhatID field to achieve a valid import ?

Thank you very much for helping me.