A while ago my terminal stopped coming up when I pressed ctrl-alt-T. Then today the terminal stopped coming up when I click on the terminanl app on the dock. I use ubuntu 18.04, a lot of python and jupyter-lab.
The only way that I know of to open terminal anymore is going to Files, and right clicking somewhere and choosing 'open in terminal'. For some reason this still works.
Why is this and how can i recover all the other ways to open terminal?
On a side note, I get an error when trying to do sudo apt-get update.
[sudo] password for user: Ign:1 http://ppa.launchpad.net/mc3man/trusty-media/ubuntu bionic InRelease Hit:2 http://security.ubuntu.com/ubuntu bionic-security InRelease Err:3 http://ppa.launchpad.net/mc3man/trusty-media/ubuntu bionic Release 404 Not Found [IP: 184.108.40.206 80] Hit:4 http://au.archive.ubuntu.com/ubuntu bionic InRelease Hit:5 http://au.archive.ubuntu.com/ubuntu bionic-updates InRelease Hit:6 http://au.archive.ubuntu.com/ubuntu bionic-backports InRelease Get:7 http://au.archive.ubuntu.com/ubuntu bionic/main Translation-en_CA [430 kB] Get:8 http://au.archive.ubuntu.com/ubuntu bionic/universe Translation-en_CA [4,118 kB] Reading package lists... Done E: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.
Theres a red error bar on the top right hand side of screen that always says "A problem occurred when checking for the updates".
I don't know if this is related.