Enable Read/Create/Edit/Delete access on the following required Standard Object Permissions:
From the Profile Detail page, click Edit and complete the steps in this section.In the old profile layout the following should help:
Marketo only supports syncing of custom objects associated with leads, contacts, and accounts.
*Transfer Lead and Transfer Record are optional but may be required if you wish for Marketo to be able to change the owner of a record
You must add each field you want synced to Marketo to your page layout; all other fields will not be synced. If you use other editions of Salesforce, Marketo will sync down all fields that the sync account has permission to access (whether or not they're in the page layout).