could it be the size of the doc or do I need to convert the pdf some how?
Thanks for getting in touch about this issue,
Our lead dev investigated your account and there seemed to be an issue with storage options that he fixed. Can you try opening the document within GroupDocs Annotation again please, and let me know? If it's still not working please attach a copy of the document with your reply (which only we can see)
Derek Hyland, Venture Lead, GroupDocs (Aspose Pty Ltd)..
Office: +1 (214) 329 1520