We are moving from one instance to another. The email program doesn't complete, it stays in Queue.
What can be the problem? Do we have to remove the smart list of campaign members? Or is it something else?
There could be a number of issues here (missing fields can be a common one) - but without visibility over any kind of error reporting it will be hard to pinpoint the exact issue.
If you're not getting an error report I would recommend that you reach out to Marketo support for this one.
Sorry not to be more helpful!