The report must also include First Name, Last Name, Company/Account, Email Address and at least one record. Without these fields your report will fail to import into Act-On.
If you would like to use the Salesforce owner to personalize the emails, a custom field will need to be created and included in the report. See Salesforce's guide to creating an 18-Digit Owner ID Field.
If you are using Salesforce Lightning, you are unable to push reports from Lightning to Act-On. This is available in Classic, so switch your view to Classic in order to push reports.