Flask+React跨域CORS问题求助：Windows正常Mac报错

报错信息 #

Access to fetch at 'http://localhost:5000/login' from origin 'http://localhost:3000' has been blocked by CORS policy
完整错误：预检请求未通过访问控制检查，请求资源缺少'Access-Control-Allow-Origin'头

环境配置 #

• 后端：Python-Flask，运行在 localhost:5000
• 前端：React，运行在 localhost:3000

已配置内容 #

Flask CORS配置 #

CORS(app, supports_credentials=True, resources={r"/*": {"origins": "*"}})

前端Fetch请求代码 #

try{
     const response = await fetch('http://localhost:5000/login', {
          method: 'POST',
          headers: {
               'Content-Type': 'application/json',
               'Access-Control-Allow-Origin': 'http://localhost:3000',
               'Access-Control-Allow-Credentials': 'true'
          },
          body: JSON.stringify(dataToSend),
          credentials: 'include'            
     })
     const data = await response.json();
     console.log("JSON Message: " + data.message);
     setPostData(data.message);
     setPostError(data.error);
            
} catch (error) {
     console.log(error);
     setPostError(error);
}

问题现状 #

1. 代码在Windows环境下完全正常，但在Mac上触发上述CORS报错
2. 已尝试Stack Overflow相关解决方案、清除Chrome浏览器缓存，问题未解决
3. 使用curl发送OPTIONS请求到http://localhost:5000/login，返回的响应头完全符合预期：

HTTP/1.0 200 OK
Content-Type: text/html; charset=utf-8
Allow: HEAD, GET, POST, OPTIONS
Access-Control-Allow-Origin: http://localhost:3000
Access-Control-Allow-Credentials: true
Access-Control-Allow-Headers: Authorization, Content-Type
Access-Control-Allow-Methods: DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT
Vary: Origin
Content-Length: 0
Server: Werkzeug/2.0.3 Python/3.9.13
Date: Sat, 30 Dec 2023 16:56:39 GMT

求各位提供可行的解决建议，感谢！

内容的提问来源于stack exchange，提问作者Josh S