Temporarily unreachable page In many cases, bloggers get this error message in their Webmaster tools dashboard. The good news is that you don’t have to worry too much about that, unless you host your site with a low quality hosting service.
The message is clear and it means that your server is briefly down, or, the specified URL returns a 501 error, and that’s a server issue that you can’t solve it from your part. Just wait a few minutes and test that page again, and see if you get the successful result.

If you’re using a free hosting, you will get that error in the majority of the time, and you know that something for free will never help your business. So, it’s the time to think about a premium hosting service for your WordPress blog or website.
I recommend
WP Engine for their high-quality service and fast customer support. No more issues with your server, because the company has technicians that will manage the technical part of your hosting. You just need to create content and never worry about the server and the site speed.
Or, if you need cheaper hosting, but for all the applications and with more flexibility and high quality, then use
Liquid Web.
If you’re using a security plugin such as Wordfence security or any other one, make sure that Googlebot can access your site and is not blocked. The majority of plugins works fine, but sometimes things can work wrong. You can verify that by disabling all your plugins, and then wait one minute or so and test the URL again.
Continue that process for each plugin, until you find the one that blocks the Googlebot from accessing your site. If you still get the same error after all that, then, contact your hosting company for support.
If your site is new and you’ve submitted it once, make sure that you have your
preferred domain name. You can set up that in your account, by following the above link. At the same time, make sure you’ve properly
submitted your blog sitemap.