如何修复web.config中失效的重写规则？HTTP重定向正常但报500错误

我正尝试通过web.config文件配置重定向，其中httpRedirect规则可正常运行，但rewrite规则失效并返回500错误。进入IIS的HTTP Redirect界面时显示异常（见下图），移除rewrite节点后该界面可正常打开。请问我哪里操作有误？

当前web.config配置如下：

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.web>
    <compilation debug="true" targetFramework="4.7.2" />
    <httpRuntime targetFramework="4.7.2" />
  </system.web>
    <system.webServer>
        <rewrite>
            <rules>
                <rule name="rewrite_client_contract" stopProcessing="true">
                    <match url="^client/contractreview/index/(.*)" />
                    <action type="Redirect" url="https://adumbsite.com/contractreview/index/{R:1}" appendQueryString="false" redirectType="Permanent" />
                </rule>
            </rules>
        </rewrite>
        <httpRedirect enabled="true" exactDestination="true" httpResponseStatus="Permanent">
            <add wildcard="/public/signup" destination="https://adumbsite.com/sign-up/" />
        </httpRedirect>
    </system.webServer>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\"Web\" /optionInfer+" />
    </compilers>
  </system.codedom>
    <system.web>
        <customErrors mode="Off"/>
    </system.web>
</configuration>

• XML配置结构非法：你的web.config里存在两个独立的<system.web>节点，XML规范要求同一父节点下不能重复定义同名节点，这会导致IIS解析配置时失败，直接触发500错误，同时破坏HTTP Redirect界面的正常加载逻辑。
• 额外需确认：IIS服务器是否已安装URL Rewrite模块，如果未安装，<rewrite>节点会被识别为无效配置，同样会引发500错误。

1. 合并重复的<system.web>节点：将两个<system.web>的内容合并为一个，确保XML结构合法。
2. 检查URL Rewrite模块：打开IIS管理器的“模块”列表，确认存在RewriteModule；若没有，需安装微软官方的URL Rewrite模块。

修正后的web.config配置：

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.web>
    <compilation debug="true" targetFramework="4.7.2" />
    <httpRuntime targetFramework="4.7.2" />
    <customErrors mode="Off"/>
  </system.web>
  <system.webServer>
    <rewrite>
      <rules>
        <rule name="rewrite_client_contract" stopProcessing="true">
          <match url="^client/contractreview/index/(.*)" />
          <action type="Redirect" url="https://adumbsite.com/contractreview/index/{R:1}" appendQueryString="false" redirectType="Permanent" />
        </rule>
      </rules>
    </rewrite>
    <httpRedirect enabled="true" exactDestination="true" httpResponseStatus="Permanent">
      <add wildcard="/public/signup" destination="https://adumbsite.com/sign-up/" />
    </httpRedirect>
  </system.webServer>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\"Web\" /optionInfer+" />
    </compilers>
  </system.codedom>
</configuration>

内容的提问来源于stack exchange，提问作者geoff swartz