File has unexpected size

edit

An error occurred when I installed ros，Here's what I do：

$ sudo sh -c '. /etc/lsb-release && echo "deb http://mirrors.ustc.edu.cn/ros/ubuntu/ $DISTRIB_CODENAME main" > /etc/apt/sources.list.d/ros-latest.list'

$ sudo apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116

$ sudo apt update

Then report an error. May I ask who knows the reason？Is it the ros mirror source that is wrong？

Get:3 http://220.112.193.195/files/1116000006474FFE/mirrors.cqu.edu.cn/ubuntu bionic/main amd64 Packages [481 kB]
Err:3 http://220.112.193.195/files/1116000006474FFE/mirrors.cqu.edu.cn/ubuntu bionic/main amd64 Packages
  File has unexpected size (1343916 != 480706). Mirror sync in progress? [IP: 220.112.193.195 80]
  Hashes of expected file:
   - Filesize:480706 [weak]
   - SHA256:a3b8443a822d1005b5a4577ede042691e4600e6597de0e76004b84678688481b
   - SHA1:d9aabcc8dcda723e7bde45f8bacbc765865edeb5 [weak]
   - MD5Sum:4f2fd4debc4d8381ac97f972a79c7286 [weak]
  Release file created at: Fri, 17 May 2019 19:32:55 +0000

Edit: Thank you for your reply. I tried to update the ros mirror source on May 28, May 29, and May 30. And i have tried using the following three mirror sources:

1. packages.ros.org
2. mirrors.ustc.edu.cn
3. mirrors.tuna.tsinghua.edu.cn

But it's all the same mistake.I even installed a new ubuntu system to try.

I used the system: ubuntu18.04

It's hard to believe that all three mirror sources are having problems at the same time,So are there any other possible causes?