When attempting to perform a link search within the workarea if there are large amounts of aliases or content items within the database the default settings can cause the link search to timeout resulting in the below error message.
A common resolution to this error is to increase the 'SqlCommandTimeoutSeconds' field within the web.config file and also add an 'executionTimeout' value into the 'httpRuntime' tag of the site's web.config file. The exact values will vary on a site to site basis, but the following settings are a good starting point for troubleshooting. If the issue persist it is recommended to reach out to developer support.
<httpRuntime executionTimeout="300" maxRequestLength="2097151" requestLengthDiskThreshold="2097151" requestValidationMode="2.0" maxUrlLength="1024" relaxedUrlToFileSystemMapping="true" />
<add key="SqlCommandTimeoutSeconds" value="60" />