Problem marking despatched on eBay.
eBay are introducing a new system for tracking IDs, which is not currently working with Packing Partner.
It looks like the system has issues because it keeps appearing, then disappearing. This means we haven't had a chance to create a fix for it.
We will post here, just as soon as we have resolved the problem.
In the mean time, please mark your sales despatched manually on eBay, then Mark despatched with Packing Partner.
Alternatively, you could look at out new add-on called Express Collect, which doesn't have this issue. See here for details