An automatic update to WordPress 5.9 software left the blog disabled.
What happened: For unknown reasons, the update did not fully complete and was missing a critical file.
The next morning, out of the blue, the blog sent me an email update on some plugins that were updated – which meant the control panel functions had come back to life.
Because the control panel was still functional, I was able to use the “Re-install 5.9” option and let it repeat the automatic update again. This time, it ran properly, and the blog is working again. The other option would have been to do a manual install, which is time consuming.