Hi, Welcome to the Deepin Forum, This post explains how the mirrors work in Deepin

https://bbs.deepin.org/post/30636

Hi.   I am also experiencing this issue, to the extent where I am unable to update my system at all.    The update request just hangs.    I have changed the mirror, but am still having issues.   
From what I understand this could effect anyone outside of the USA or China currently due to locations of CTN Servers.      
I believe it was over a week ago, the last time I was able to connect.

Hi, Try to update from terminal, and if still not working upload screenshot of your terminal output.

Hi
The out put is below - the command will just hang in this state:
Ign:1 http://dl.google.com/linux/talkplugin/deb stable InRelease
Get:2 http://dl.google.com/linux/talkplugin/deb stable Release [1,347 B]      
Get:3 http://dl.google.com/linux/talkplugin/deb stable Release.gpg [198 B]     
Get:4 http://repository.spotify.com stable InRelease [3,302 B]                 
Ign:5 http://repo.vivaldi.com/stable/deb stable InRelease            
Get:6 http://repo.vivaldi.com/stable/deb stable Release [2,709 B]   
Get:7 http://dl.google.com/linux/talkplugin/deb stable/main amd64 Packages [730 B]
Get:8 http://dl.google.com/linux/talkplugin/deb stable/main i386 Packages [724 B]
Get:9 http://repo.vivaldi.com/stable/deb stable Release.gpg [819 B]            
Get:10 http://repository.spotify.com stable/non-free amd64 Packages [1,595 B]
Get:11 http://repository.spotify.com stable/non-free i386 Packages [1,133 B]   
Get:12 https://deb.opera.com/opera-beta stable InRelease [2,592 B]   
Get:13 https://deb.opera.com/opera-developer stable InRelease [2,592 B]     
Get:14 http://repo.vivaldi.com/stable/deb stable/main amd64 Packages [2,069 B]
Get:15 https://deb.opera.com/opera-beta stable/non-free amd64 Packages [1,803 B]
Get:16 https://deb.opera.com/opera-beta stable/non-free i386 Packages [1,798 B]
Get:18 http://repo.vivaldi.com/stable/deb stable/main i386 Packages [2,096 B]
0% [Connecting to]   

You can try sudo apt-get clean and try again .
Its not indicating what its trying to connect to. You mentioned you changed the mirror. What mirror are you using and how did you change it ?