I tried to update Debian 9 to Debian 10--that didn't work. I then installed Debian 10 from scratch. I later installed CuteCom from Debian using Synaptic (having to have root privileges). But now I can't use CuteCom because it says I don't have the right permissions. I can't get root privileges anymore on my own computer. I always get "su: Authentication failure". I have gone thru the Grub menu several times to add and repeat a root "passwd" but that doesn't work either.
Is there any way for me to get the ability to use my own computer with Debian 10?