Did you accidentally block Google from accessing your web site? Google says you don't have to worry, while there may be short term damage caused by it, you should recover.
Google's John Mueller said it should not result in "long term damage."
Here is how John put it:
From our point of view, once we're able to recrawl and reprocess your URLs, they'll re-appear in our search results. There's generally no long-term damage caused by an outage like this, but it might take a bit of time for things to get back to "normal" again (with the caveat that our algorithms change over time, so the current "normal" may not be the same state as it was before).
So if your hosting company has issues or you slip up and block Google, once Google can crawl again, in the long run, you should be okay.
Forum discussion at Google Webmaster Help.
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