I can't download new Plasma widgets and Plasma themes in Kubuntu 16.04 LTS

Question

Each time I try to download the new Plasma widget from the Plasma Add-On Installer, I get the following error:

Loading of providers from file: http://download.kde.org/ocs/providers.xml failed

Screenshot:

The same problem is also happening when I am trying to install new theme. Please check the below screenshot for clarification:

Any suggestions, comments or answers will always be appreciated. Thanks.

Answer 1

I found about 20 files in /etc/xdg/ that all reference

ProvidersUrl=http://download.kde.org/ocs/providers.xml

I think the download.kde server currently sends a redirect to

https://autoconfig.kde.org/ocs/providers.xml

But I guess its not followed.

Answer 2

Type https://autoconfig.kde.org/ocs/providers.xml in browser.

Copy contents.

Create a providers.xml file and paste them into it.

Go to /etc/xdg/

Change this line

ProvidersUrl=http://download.kde.org/ocs/providers.xml

to

ProvidersUrl=file:///path/to/your/custom/xml/file/providers.xml

in all the files that have it.

I'm sure there is a single terminal command you can use to do that in all files, but I don't know what that is. Maybe someone can improve this answer. I suggest changing it on a single file first and testing the corresponding app first. The file that corresponds to the plasma add-on installer mentioned should have a pretty obviously fitting name.

I found the info in this guide and followed it myself for a different error: https://bugs.launchpad.net/ubuntu/+source/kde-runtime/+bug/1610665

I'm not sure why just changing the line to

ProvidersUrl=https://autoconfig.kde.org/ocs/providers.xml

wouldn't work. I can't test that, because I don't have the question's error.

Or why the guide uses a local path url that doesn't seem to work on my end...I posted here what worked for me.