LibreOffice causes me to log out forcefully

I am using LibreOffice Writer for write a book about matrices in math, but when I start to typing on this application, my screen goes black with white dash blinking on left upper corner and displaying login screen.

My question is why this issue can happen on my laptop?. If it continues like this, I can’t use my old laptop comfortably for making documents, or anything that using LibreOffice wholly. I use LibreOffice from default installation of Linux Mint.

OS version : Linux Mint 21
LibreOffice version :

You have a problem, OK. But try to describe in such a way that people not knowing your computer and unable to see you and your screen can understand the issue.

Edit your question (Don’t use a comment at this stage. This site is not a forum but a Question a Answer one. So group all useful information at a single location) to provide minimal details:

  • OS name (and in case of Linux, desktop manager such as GNOME, KDE Plasma, Xfce, …)
  • LO version
  • where you got LO and how you installed it

What you describe looks like a full-screen terminal window where you can enter commands

First steps

Please try step 5, 2, 7; in this order.

Report here again.

Seems you are not the only one with Mint21.

In this Mint-Tread the topic was solved with a complete purge of LO and reinstalling from LibreOffice-fresh-PPA: