This article describes an issue with Episerver page search in Edit mode. In this instance it appears to only work when using IDs in the search field.
The first step is to try browsing to the service URL locally on the server. It would look like this and match the url in your configuration. For example:
the URL would be:
If everything was set up properly, the response would say Method not allowed as in the image below.
However, if this is the mentioned problem it is likely to get a 404 Not Found page instead. This may be due to missing Handler Mappings in the IIS. To check this, left click on your website in the IIS, and select Handler Mappings. Scroll down and see if you can find any with the path *.svc
If none are found then open up the Control Panel.
Go to Programs and Features and click the Turn Windows features on or off link. Here tick the HTTP Activation checkbox as in the image. The same thing on the Windows Server environment below.
Information provided from here.