*DM Login problems?

Question

linux

After turning off the power, the following problem arose when trying to login to kdm / sddm after entering the login / password in kdm - a splash screen appears, the cursor and nothing happens, in sddm - the cursor turns into a cross and nothing else happens.
This happens no matter where you log in (I've tried kde, twm, "safe mode").
I also tried to create a new user and log in from under him - but this did not affect the situation.
I can log in to the console under both users.
If you do startx and then startkde as root, then kde starts up and works.
if I do startx from one of the normal users, twm opens and the system stops responding to any input.
fsck did.
in ~/.xsession-errors there is only:
>sudo: no tty present and no askpass program specified
Distribution - Arch.
Tell me please, what could be the matter?

Answer 1

In general, to begin with, return the original sudoers to their place.
And then thoughtfully make changes.

Answer 2

see logs
/var/log/kdm.log
/var/log/Xorg.0.log
/var/log/Xorg.0.log.old
and also system log:
journalctl