Sitecore - Could not find configuration node: contentSearch/indexConfigurations/indexUpdateStrategies/syncMaster

When I use "sitecore_web_index" for Sitecore.ContentSearch.ContentSearchManager.GetIndex, This happens on the content delivery server instance.

Exception: System.InvalidOperationException
Message: Could not find configuration node: contentSearch/indexConfigurations/indexUpdateStrategies/syncMaster
Source: Sitecore.Kernel
   at Sitecore.Configuration.Factory.GetConfigNode(String xpath, Boolean assert)
   at Sitecore.Configuration.Factory.CreateObject(String configPath, String[] parameters, Boolean assert)

The reason for this exception that is because there is no 'syncMaster' index update strategy.
Also, the List Manager was enabled. I must have disable List Manager on a content delivery server.

The configuration file of 'sitecore_list_index'(no sitecore_web_index) use syncMaster index update strategy as below.

Sitecore.ListManagement.Lucene.Index.List.config:

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <contentSearch>
      <configuration type="Sitecore.ContentSearch.ContentSearchConfiguration, Sitecore.ContentSearch">
        <indexes hint="list:AddIndex">
          <index id="sitecore_list_index" type="Sitecore.ContentSearch.LuceneProvider.LuceneIndex, Sitecore.ContentSearch.LuceneProvider">
            <param desc="name">$(id)</param>
            <param desc="folder">$(id)</param>
            <!-- This initializes index property store. Id has to be set to the index id -->
            <param desc="propertyStore" ref="contentSearch/indexConfigurations/databasePropertyStore" param1="$(id)" />
            <configuration ref="listManagementSearch/indexConfigurations/listManagementLuceneIndexConfiguration" />
            <strategies hint="list:AddStrategy">
              <!-- NOTE: order of these is controls the execution order -->
              <strategy ref="contentSearch/indexConfigurations/indexUpdateStrategies/syncMaster" />

I deleted this file and the error was resolved.

Thanks,