Cannot install ubuntu budgie themes 18.04

I’m a linux noob. I chose Ubuntu budgie 18.04. I installed it on my laptop to test it out and it works wonders. I can change my themes and all that. I installed in on my computer too to use it as a daily driver. After doing some updates I noticed that I get an error whenever I try to install a theme from Budgie Themes and Layouts. Are there updates that I didn’t do that allow theme installations? If so, can I get a list of updates/installs that I have to put in linux in order for theme installations to work? I also tried reinstalling Ubuntu Budgie but most of the themes aren’t working. Pocilo and Arc Design are working.

For reference, the error I get says “Failed installation of material-materia2-theme”. Doesn’t help much but I thought I’d put this in.

Open a terminal (tilix)


sudo apt update && sudo apt dist-upgrade

What is the output that you see? (copy - paste here)

Site error: Sorry, new users can only put 2 links in a post.

For some reason you have lost the security key for a PPA.

Copy paste the following into a terminal:

sudo apt-key adv --keyserver --recv-keys B76E53652D87398A

Followed by:

sudo apt update && sudo apt dist-upgrade

Hopefully no more errors will be visible now when running the above.