Exchange Web Service synchronising error

Hi there,
has anyone else had this error?

Does it; a) mean not all emails are downloaded and b) how does one fix it?

[Exchange Web Services] Synchronizing folder ‘Inbox’ failed due to the following error: Unexpected end of file has occurred. The following elements are not closed: t:Content, t:FileAttachment, m:Attachments, m:GetAttachmentResponseMessage, m:ResponseMessages, m:GetAttachmentResponse, s:Body, s:Envelope. Line 1, position 999641.

best,
S