ubuntu 16.04 update failure

[elim-qiu]

395 upgraded, 0 newly installed, 0 to remove and 28 not upgraded.
Need to get 49.7 MB/587 MB of archives.
After this operation, 97.8 MB of additional disk space will be used.
Do you want to continue? [Y/n]
Err:1 https://deb.opera.com/opera-stable stable/non-free amd64 opera-stable amd64 45.0.2552.635
404 Not Found
E: Failed to fetch https://deb.opera.com/opera-stable/pool/non-free/o/opera-stable/opera-stable_45.0.2552.635_amd64.deb 404 Not Found


tried
sudo apt-get install --reinstall ubuntu-extras-keyring
gpg --keyserver keyserver.ubuntu.com --recv 3E5C1192
gpg --export --armor 3E5C1192 | sudo apt-key add -


sudo apt-get updateIgn:1 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu xenial InRelease
Hit:3 http://dl.google.com/linux/chrome/deb stable Release
Get:4 http://us.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]
Hit:5 http://ppa.launchpad.net/ondrej/php/ubuntu xenial InRelease
Hit:6 http://archive.canonical.com/ubuntu xenial InRelease
Get:7 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Hit:9 http://www.geogebra.net/linux stable InRelease
Get:10 http://us.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB]
Hit:8 http://screenshots.getdeb.net xenial-getdeb InRelease
Get:12 https://deb.opera.com/opera-stable stable InRelease [2,592 B]
Err:12 https://deb.opera.com/opera-stable stable InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D615560BA5C7FF72
Fetched 309 kB in 2s (151 kB/s)
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://deb.opera.com/opera-stable stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D615560BA5C7FF72
W: Failed to fetch https://deb.opera.com/opera-stable/dists/stable/InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D615560BA5C7FF72
W: Some index files failed to download. They have been ignored, or old ones used instead


sudo apt-get upgrade 395 upgraded, 0 newly installed, 0 to remove and 28 not upgraded.Need to get 49.7 MB/587 MB of archives.
After this operation, 97.8 MB of additional disk space will be used.
Do you want to continue? [Y/n]
Err:1 https://deb.opera.com/opera-stable stable/non-free amd64 opera-stable amd64 45.0.2552.635
404 Not Found
E: Failed to fetch https://deb.opera.com/opera-stable/pool/non-free/o/opera-stable/opera-stable_45.0.2552.635_amd64.deb 404 Not Found





Thanks in advance for your help!

[elim-qiu]

By far the simplest way to handle this now is with Y-PPA-Manager (which now integrates the launchpad-getkeys script with a graphical interface).

To install it, first add the webupd8 repository for this program:
sudo add-apt-repository ppa:webupd8team/y-ppa-manager

Update your software list and install Y-PPA-Manager:
sudo apt-get update
sudo apt-get install y-ppa-manager

Run y-ppa-manager (i.e. type y-ppa-manager then press enter key).

When the main y-ppa-manager window appears, click on "Advanced."

From the list of advanced tasks, select "Try to import all missing GPG keys" and click OK.
You're done! As the warning dialog says when you start the operation, it may take quite a while (about 2 minutes for me) depending on how many PPA's you have and the speed of your connection.

[BenginM]

Hiya , if you disable these third party PPA's you shouldn't have trouble updatin' in the first place. as for a GPG key issues, one should consult the official site for such third party package and add the new updated key probably.