Please, it would help us keep things organized and make it easier for others to find answers to the same questions if you ask one question per thread and use the appropriate forum for your question. This is the developer forum, as the description says it is for discussing working with the source code in Visual Studio. I will answer your first question here though it would have been a better fit for the Installation forums since it is a configuration question. Please start a new thread in the "Questions about Site Administration" forum and ask your blog question there.
If your site does not resolve from DNS then you should wait until after DNS is setup before you enable the AppKeepAlive. It makes a server side web request to your home page often enough to keep your site awake, but if it can't resolve the DNS it will just timeout as your error indicates.
As indicated in the AppKeepAlive documentation, if you are hosted in IIS 7 with an Integrated pipeline app pool then you need to specify the url for the root of your site. However if your app pool is Classic instead of Integrated, then you need to leave the url blank or it can cause this error.
Hope it helps,