Lightroom to blurb

[nand]

When uploading a book to blurb it stops when into process and says problem uploading. It will render photo and start
and then stall. My photo are Raw in sRgb. I was under the impression i did not have to use jpeg. is that correct ??? What can make it stall

[Victoria Bampton]

Does it always stall at the same point? Raw files are fine, so it shouldn't be that. Are all of the files available (i.e. none marked as missing or corrupted)?