问redhat linux 使用docker-compose 部署应用出现如下错误？

什么添加国内源已经试过。还是一样报错。

> [4/4] RUN pip install -r requirements.txt -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com:

#0 2.405 Looking in indexes: http://pypi.douban.com/simple/

#0 7.424 WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPConnection object at 0x7f2bfab1a950>: Failed to establish a new connection: [Errno -3] Try again')': /simple/flask/

#0 12.95 WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPConnection object at 0x7f2bfa33b190>: Failed to establish a new connection: [Errno -3] Try again')': /simple/flask/

#0 18.96 WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPConnection object at 0x7f2bfa33b890>: Failed to establish a new connection: [Errno -3] Try again')': /simple/flask/

#0 25.98 WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPConnection object at 0x7f2bfa9d35d0>: Failed to establish a new connection: [Errno -3] Try again')': /simple/flask/

#0 35.00 WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPConnection object at 0x7f2bfa348090>: Failed to establish a new connection: [Errno -3] Try again')': /simple/flask/

#0 40.01 ERROR: Could not find a version that satisfies the requirement flask (from versions: none)

#0 40.02 ERROR: No matching distribution found for flask