WordPress MultiSite 404 on Admin Dashboard

If you are experiencing a 404 when switching to the dashboard of a given site, verify the web.config is accurate. We’ve found that older versions of WordPress have incorrect rules within web.config. Try the following web.config:

  <?xml version="1.0" encoding="UTF-8"?>
  <configuration>
  <system.webServer>
  <rewrite>
  <rules>
    <rule name="WordPress Rule 1" stopProcessing="true">
      <match url="^index\\.php$" ignoreCase="false" />
      <action type="None" />
    </rule>
    <rule name="WordPress Rule 2" stopProcessing="true">
      <match url="^(\[_0-9a-zA-Z-\]+/)?wp-admin$" ignoreCase="false" />
      <action type="Redirect" url="{R:1}wp-admin/" redirectType="Permanent" />
    </rule>
    <rule name="WordPress Rule 3" stopProcessing="true">
      <match url="^" ignoreCase="false" />
      <conditions logicalGrouping="MatchAny">
          <add input="{REQUEST_FILENAME}" matchType="IsFile" ignoreCase="false" />
          <add input="{REQUEST_FILENAME}" matchType="IsDirectory" ignoreCase="false" />
      </conditions>
      <action type="None" />
    </rule>
    <rule name="WordPress Rule 4" stopProcessing="true">
      <match url="^(\[_0-9a-zA-Z-\]+/)?(wp-(content|admin|includes).*)" ignoreCase="false" />
      <action type="Rewrite" url="**{R:2}**" />
    </rule>
    <rule name="WordPress Rule 5" stopProcessing="true">
      <match url="**^(\[_0-9a-zA-Z-\]+/)?(.*\\.php)$**" ignoreCase="false" />
      <action type="Rewrite" url="{R:2}" />
    </rule>
    <rule name="WordPress Rule 6" stopProcessing="true">
      <match url="." ignoreCase="false" />
      <action type="Rewrite" url="index.php" />
    </rule>
  </rules>
  </rewrite>
  </system.webServer>
  </configuration>