That the uid in toc.ncx (49a3df67-d531-4839-b41c-f9f1fc1c4a60) should be the same as in content.opf (
urn:uuid:49a3df67-d531-4839-b41c-f9f1fc1c4a60). Right now they differ in the red part.
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And, by the way, you should have given a more descriptive title for your thread. I've fixed it now for you.