A large number of my contacts show as unsubscribed after Salesforce connection.

If you have noticed a large influx in unsubscribed status records in your account after you connected the Salesforce integration, it's likely that those records already existed in your account but the Delivra Opt-In checkbox is not marked for them in Salesforce.

How the Delivra Opt-in check works:

1. If a lead/contact record from Salesforce does not exist in your Delivra account and the lead/contact record does not have the Delivra Opt-In checked, no sync will occur for that lead/contact. 

2. If a lead/contact record from Salesforce does exist in your Delivra account and the lead/contact record does not have the Delivra Opt-In checked, the lead/contact record will be included in the sync and be updated to unsubscribe status in your Delivra account.