Err:35 http://103.1.138.199/ppa.launchpad.net/cairo-dock-team/ppa/ubuntu xenial/main amd64 Packages 404 Not Found

The PPA ppa:cairo-dock-team/ppa does not provide software for xenial.
You have to remove it from the list of repository sources (e.g. in the configuration dialogue of update-manager).

@Manfred. I am confuse with your reply. There is a webpage from this
project providing for Xenial
https://launchpad.net/ubuntu/xenial/+source/cairo-dock. What do you mean
by "does not provide software for xenial"? Are you also saying that
Cairo-dock is not compatible to Xenial?

On 03/03/2017 18:44, Manfred Hampl wrote:
> Your question #521119 on Cairo-Dock Core changed:
> https://answers.launchpad.net/cairo-dock-core/+question/521119
>
> Status: Open => Answered
>
> Manfred Hampl proposed the following answer:
> The PPA ppa:cairo-dock-team/ppa does not provide software for xenial.
> You have to remove it from the list of repository sources (e.g. in the configuration dialogue of update-manager).
>

@Manfred. Thank you for your explanation. I have removed the ppa. :)

04/03/2017 03:46, Manfred Hampl wrote:
> Your question #521119 on Cairo-Dock Core changed:
> https://answers.launchpad.net/cairo-dock-core/+question/521119
>
> Status: Open => Answered
>
> Manfred Hampl proposed the following answer:
> Your system settings are as such that you are looking for software in the standard repositories for Ubuntu, but also in an extra PPA (personal package archive).
> And this PPA ppa:cairo-dock-team/ppa does not provide software for Ubuntu xenial, but only for older Ubuntu releases, see https://launchpad.net/~cairo-dock-team/+archive/ubuntu/ppa/+packages (version of cairo-dock 3.4.1 for xenial, and lower ones for older releases)
>
> The standard Ubuntu repositories have current verions for xenial and
> newer, see https://launchpad.net/ubuntu/+source/cairo-dock
>
> So you do not need the reference to the PPA, but having it creates error
> messages.
>

Do you still get errors when running the command
sudo apt-get update
or does it work now as expected?

I do not have the warning anymore during sudo apt-get update.

However, I am getting intermittent hanging of cairo-docks at times.
At the moment, I have to run ps -ef | grep cairo-dock, get the process number, kill the process and rerun cairo-dock.
I noticed the process that i am running is using the -c option. I will try to use -o to see if there is any improvement to my situation. If I have. i will raise another question as my present question has been answered.

Thanks Manfred Hampl, that solved my question.