A small matter yet will cause a major problem and usually happens more often than you imagine: forgetting to unblock search engines from crawling your site.
When your website is under maintenance, you set to block the search engines to crawl, to stop the search engines looking for updated text and links, then indexed the unfinalized website content in which may affect your site rankings.
However, once the site is done, you get exhilarated with the new design and publish it immediately. Hours later after the launching, you notice something is wrong when your website is not showing in Google search results. This scenario also happened to me once. I got panicked and immediately reviewed my site looking for the possible error.
From then I found out my mistake, I forgot to unblock robots from crawling and indexing my website. A simple check mark that you can find in WordPress settings or a simple text file placed on the web server informing web crawlers that they can now access the site.
It’s not unusual to commit this kind mistake even if you double check your website, with a lot of things going on our mind we sometimes forget the small details because we are too focused on the larger ones. However, this mistake can be avoided by checking with Google Webmaster tools to ensure your site is indexed.