Windows环境下使用pyodbc连接SQL Server失败求助

我在Windows系统里用pyodbc连接SQL Server的时候一直连不上，我的操作步骤是这样的：

import pyodbc as odbc
import pandas as pd

cnxn=odbc.connect(cnxn_str)

到最后执行odbc.connect(cnxn_str)这一步的时候，就弹出了下面的错误：

OperationalError                          Traceback (most recent call last)
Cell In[25], line 1
----> 1 cnxn=odbc.connect(cnxn_str)

OperationalError: ('08001', '[08001] [Microsoft][ODBC Driver 17 for SQL Server]SQL Server Network Interfaces: Error Locating Server/Instance Specified [xFFFFFFFF].  (-1) (SQLDriverConnect); [08001] [Microsoft][ODBC Driver 17 for SQL Server]Login timeout expired (0); [08001] [Microsoft][ODBC Driver 17 for SQL Server]A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online. (-1)')

我已经确认过服务器名称是对的，也检查了1433端口的情况，还是解决不了，有没有大佬能帮我看看呀？

备注：内容来源于stack exchange，提问作者Mohamed Ansary