Based on the fact that you are able to download some messages, it seems likely that the message in question (id 4886) has bad/unexpected content.
If it is always getting stuck on the same message, you may be able to get around the problem by deleting it through ZWC.
Use the query 'item:4886' to find this item.
If the problem is occurring for *all* accounts on this server then SSL configuration might be the problem.
The 'bad record MAC' error can mean that there is a mismatch between public and private keys or some similar mismatch in the SSL layer.