(Yes, this is a duplicate of an unanswered question. I tried to post on it, but my post was deleted, so I'm asking the same question, but my own way.)
I'm unable to add the LibreOffice repo. Here's what I did and the result:
steve@ubuntu:~$ sudo add-apt-repository ppa:libreoffice/ppa Cannot add PPA: 'ppa:~libreoffice/ubuntu/ppa'. ERROR: '~libreoffice' user or team does not exist.
My internet connection is fine, I have (and need) no proxy for internet access. Command like
sudo apt update sudo apt upgrade work fine and in fact, I run both every time I start up the system (largely because VSCode-insiders updates every day.)
Answers to the OP seem to indicate that the tilde in the PPA name is my problem, but I AM NOT ENTERING A TILDE! It seems that apt-get-repository is adding it for me. I have not found anyone else having this issue adding the LibreOffice PPA, so it must be my fault, but I have no idea what I could have done to cause this. In fact, this is the first time I have ever even tried to use apt-add-repository.