- apt update
After that we're going to uninstall the old Firefox from our Ubuntu to do that, launch your terminal and type the command
- apt autoremove firefox
Now we're going to make sure out Gnupg is up to date or installed, to do that type the command
- apt Install gnupg
Now we're going to add Debian repository to our ubuntu sources repo, to do that, type or copy the command
- echo "deb http://ftp.debian.org/debian stable main contrib non-free" >> /etc/apt/sources.list
now to update the newly added Debian repository we type the command
- sudo apt update
and now we should get an error that says "the following signatures couldn't be verified because the public key is not available" .
To fix that copy or type the commands below in your terminal
- apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-keys 648ACFD622F3D138
- apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-keys 0E98404D386FA1D9
- apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-keys 605C66F00D6C9793
after that you can now update your repository again by using the command
- apt update
Now we're going to install mozilla Firefox again by using the command
- apt Install firefox-esr
And this should fix the Ubuntu browser issue , and from now on our browser should be readily available.