They’re silent on the topic, which is most annoying. Even a response like “buy the premium version” would be better than not addressing the issue (note: I’ll do something else before I buy the premium version just to add Instagram).
I’ve been looking at getting it to work always… can you give the errors you’re seeing with MailPoet or any other plugin? I’ve tested it against a large number, but obviously haven’t got them all.
If I upload the file via FTP (after uploading it through DLM), the corruption problem appears to disappear. Note that the file sizes are identical uploading both ways.