Relevant Product: Mail Archiver
Use the IIS Management Console to ensure that the site is running and IIS is operational.
Check the Application Event Log and Exclaimer Application Event Log to see if there are any errors from Mail Archiver or IIS.
Run an IISReset and look for any errors when IIS starts.
Check you are using the correct port. The default port is 53444 out-of-the-box. This is found in the IIS Management Console. The port mentioned in the console is used for Batch Importer and not for the website.
Try browsing to the Web Search from the computer that has Mail Archiver installed on it. This will confirm if there is a firewall issue.