always reports this error when downloading the configuration file while configuring the coolfly agent. At first, I thought it was the problem that the agency website gave out there, stalling for a long time is not good. Then during wine installation today, after adding the PPA Channel, execute the Apt-get Update to report the same error. The error was finally found at

set before the proxy address, not changed back.

--2020-02-18 12:10:33--  https://rbq.caipin.pro/link/cias4tBlguQQ9EVF?clash=1
Connecting to 127.0.0.1:7890... failed: Connection refused.

although (set) inside (network proxy) was changed back to automatic, it could be seen from env| grep-i proxy command that the system was still accessed through the proxy port, but VPN was not set successfully at this time, so it became unable to download.

i2@i2:~/Downloads $ env|grep -I proxy
http_proxy=http://127.0.0.1:7890/
socks_proxy=socks://127.0.0.1:7891/
https_proxy=https://127.0.0.1:7890/

the solution is as follows [1] :

$ unset http_proxy
$ unset https_proxy
 
$ env|grep -I proxy
未输出任何东西

Specific reference:

[1]
the author: no slope of the former Soviet union
link: https://www.jianshu.com/p/d6730c16a4c9
source: Jane books
copyright owned by the author. Commercial reprint please contact the author for authorization, non-commercial reprint please indicate the source.