apt-get update cannot connect to server

I try to get update on my Ubuntu 15.04 but if failed to connect to server

me@me:~$ sudo apt-get update 
Err http://archive.ubuntu.com vivid InRelease
Err http://archive.ubuntu.com vivid-updates InRelease
Err http://archive.ubuntu.com vivid-backports InRelease
Err http://archive.ubuntu.com vivid-security InRelease
Err http://archive.ubuntu.com vivid Release.gpg
  Unable to connect to 54.86.15.42:8080:
Err http://archive.ubuntu.com vivid-updates Release.gpg
  Unable to connect to 54.86.15.42:8080:
Err http://archive.ubuntu.com vivid-backports Release.gpg
  Unable to connect to 54.86.15.42:8080:
Err http://archive.ubuntu.com vivid-security Release.gpg
  Unable to connect to 54.86.15.42:8080:
Reading package lists... Done
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid/InRelease  
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid-updates/InRelease  
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid-backports/InRelease  
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid-security/InRelease  
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid/Release.gpg  Unable to connect to 54.86.15.42:8080:
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid-updates/Release.gpg  Unable to connect to 54.86.15.42:8080:
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid-backports/Release.gpg  Unable to connect to 54.86.15.42:8080:
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/vivid-security/Release.gpg  Unable to connect to 54.86.15.42:8080:
W: Some index files failed to download. They have been ignored, or old ones used instead

I tried to find solutions but cannot fix it. Here what I tried so far:

1. Modify in /etc/resolv.conf to:

   nameserver 8.8.8.8
   nameserver 8.8.8.4
   

2. I tried to ping Ubuntu server

   me@me:~$ ping archive.ubuntu.com
   PING archive.ubuntu.com (91.189.91.15) 56(84) bytes of data.
   64 bytes from likho.canonical.com (91.189.91.15): icmp_seq=1 ttl=41 time=259 ms
   64 bytes from likho.canonical.com (91.189.91.15): icmp_seq=2 ttl=41 time=257 ms
   64 bytes from likho.canonical.com (91.189.91.15): icmp_seq=3 ttl=41 time=255 ms
   64 bytes from likho.canonical.com (91.189.91.15): icmp_seq=4 ttl=41 time=288 ms
   ^C
   --- archive.ubuntu.com ping statistics ---
   4 packets transmitted, 4 received, 0% packet loss, time 3003ms
   rtt min/avg/max/mdev = 255.160/265.270/288.347/13.437 ms
   

3. In Software & Update, change server to Main Server

4. In /etc/apt/apt.conf I found this line:

   Acquire::http::proxy 54.86.15.42:8080
   

   I tried to add # in front of it and didn't work. Then try to connect to 54.86.15.42:8080 and nothing happens. And ping to this address:

   me@me:~$ sudo ping 54.86.15.42
   PING 54.86.15.42 (54.86.15.42) 56(84) bytes of data.
   ^C
   --- 54.86.15.42 ping statistics ---
   16 packets transmitted, 0 received, 100% packet loss, time 14999ms
   

It seems related to proxy or firewall but I don't use any of them. Does anybody know how to fix this?

Solution 1:

My problem was solved. I don't know what makes it works again. I tried these command unset http_proxy and unset https_proxy as @nilesh_101 suggested. One more thing I did is change proxy and then change it to default again. Thanks all you guys for answering my question!

Solution 2:

I had the same problem.Then i clear all the contents of apt.conf file and it works perfectly.