I've tried all the 7 steps described there
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Can you tell me the titles of the ebooks? If the mobi file is over the 50mb limit that Amazon sets for that service, they won't send to Kindle. In that case, you would have to use an alternate method for getting the mobi file onto your Kindle, such as downloading it directly from your oreilly.com account to your Kindle, or plugging the Kindle into your computer and copying the mobi file to the Documents folder on the Kindle.
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