We have set up journey in Marketing Cloud using Salesforce data as an entry source. I am observing individual email results records in Sales cloud and found that some of them have not flown back to Sales Cloud. In Email studio tracking I see total sent (delivered) are 35, while I only see 13 IERs in Sales cloud. Some of the email were sent 5 days ago. I assume that it won't take that long for the tracking to flow into Sales Cloud. Does anyone have any ideas why this happens? Thank you.
You can request tracking immediately, to see if it can pull over the tracking data - if this works, then you know the connector is working.
If it doesn't flow over, it means there's an issue with your connector - and a support case would be the best way to resolve. (Can be a number of things, out of date oauth token, a bug, other)