Posting to Attachment API is not working

I am getting 404 errors when trying to GET an attachment.
First I POST to https://api.servicem8.com/api_1.0/attachment.json which gives me a 200 and x-record-uuid value. I then use this x-record-uuid value and perform a GET to https://api.servicem8.com/api_1.0/attachment/x-record-uuid.json. I now get a 404 which makes it impossible to send the actual attachment. This was previously working, but has stopped over the last few days. Any ideas?