# Sudo rejects valid password ("Sorry, try again") while su - works flawlessly
### System Environment
* **OS:** CachyOS x86_64
* **DE/WM:** KDE Plasma / KWin (Wayland)
* **Shell:** fish
* **User Groups:** `wheel`, `nopasswdlogin` (Auto-login enabled)
---
### Description of the Bug
During an active session, `sudo` completely stopped accepting my correct user password, consistently returning "Sorry, try again." This behavior persisted across new terminal tabs and windows, effectively locking me out of standard admin commands despite entering the proper credentials.
### Steps Taken / Observations
1. **`su -` worked perfectly:** Running `su -` accepted my password instantly and granted root access. This proves the account data wasn't corrupted and the password phrase was completely correct.
2. **Faillock resets failed:** From the working root prompt, running `faillock --user <username> --reset` did nothing to fix the `sudo` block.
3. **Password override failed:** Running `passwd <username>` from the root prompt successfully updated and overwrote the password files. However, back in the normal user terminal, `sudo` *still* rejected the newly created password with the same "Sorry, try again" loop.
4. **Snapshot Rollback Required:** The issue appeared to be a total desync between the active PAM session, the Wayland environment, and user authentication. Because the system state was stuck in memory, I was forced to roll back to a system snapshot, resulting in a loss of recent setups.
---
### System Configurations
**Output of `/etc/pam.d/sudo`:**
```text
#%PAM-1.0
auth include system-auth
account include system-auth
session include system-auth
```
**Output of `groups`:**
```text
<username> : <username> sys network wheel audio lp storage video users rfkill nopasswdlogin
System:
Kernel: 7.0.10-1-cachyos arch: x86_64 bits: 64
Desktop: KDE Plasma v: 6.6.5 Distro: CachyOS
Machine:
Type: Desktop Mobo: ASUSTeK model: ROG STRIX B450-F GAMING v: Rev 1.xx
serial: <superuser required> Firmware: UEFI vendor: American Megatrends
v: 5901 date: 10/03/2025
CPU:
Info: 8-core model: AMD Ryzen 7 5700X3D bits: 64 type: MT MCP cache:
L2: 4 MiB
Speed (MHz): avg: 1751 min/max: 575/4151 cores: 1: 1751 2: 1751 3: 1751
4: 1751 5: 1751 6: 1751 7: 1751 8: 1751 9: 1751 10: 1751 11: 1751 12: 1751
13: 1751 14: 1751 15: 1751 16: 1751
Graphics:
Device-1: Advanced Micro Devices [AMD/ATI] Navi 21 [Radeon RX 6800/6800 XT
/ 6900 XT] driver: amdgpu v: kernel
Display: wayland server: Xwayland v: 24.1.11 compositor: kwin_wayland
driver: gpu: amdgpu resolution: 3840x2160~60Hz
API: EGL v: 1.5 drivers: radeonsi,swrast
platforms: gbm,wayland,x11,surfaceless,device
API: OpenGL v: 4.6 vendor: amd mesa v: 26.1.1-arch2.1 renderer: AMD
Radeon RX 6800 (radeonsi navi21 ACO DRM 3.64 7.0.10-1-cachyos)
API: Vulkan v: 1.4.350 drivers: radv surfaces: N/A
Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo
de: kscreen-console,kscreen-doctor wl: wayland-info x11: xdpyinfo,xprop
Audio:
Device-1: Advanced Micro Devices [AMD/ATI] Navi 21/23 HDMI/DP Audio
driver: snd_hda_intel
Device-2: Advanced Micro Devices [AMD] Starship/Matisse HD Audio
driver: snd_hda_intel
API: ALSA v: k7.0.10-1-cachyos status: kernel-api
Server-1: PipeWire v: 1.6.5 status: active
Network:
Device-1: Intel I211 Gigabit Network driver: igb
IF: enp4s0 state: down mac: <filter>
Device-2: Intel Wi-Fi 6E AX210/AX1675 2x2 [Typhoon Peak] driver: iwlwifi
IF: wlan0 state: up mac: <filter>
Bluetooth:
Device-1: Intel AX210 Bluetooth driver: btusb type: USB
Report: btmgmt ID: hci0 state: up address: <filter> bt-v: 5.4
Drives:
Local Storage: total: 8.43 TiB used: 4.89 TiB (58.1%)
ID-1: /dev/nvme0n1 vendor: Samsung model: SSD 980 PRO with Heatsink 2TB
size: 1.82 TiB
ID-2: /dev/nvme1n1 vendor: Samsung model: SSD 970 PRO 512GB
size: 476.94 GiB
ID-3: /dev/sda vendor: Seagate model: edited size: 1.82 TiB
ID-4: /dev/sdb vendor: Western Digital model: edited
size: 3.64 TiB
ID-5: /dev/sdc vendor: Toshiba model: edited size: 698.64 GiB
type: USB
Partition:
ID-1: / size: 1.82 TiB used: 291.27 GiB (15.6%) fs: btrfs
dev: /dev/nvme0n1p2
ID-2: /boot/efi size: 511 MiB used: 664 KiB (0.1%) fs: vfat
dev: /dev/nvme0n1p1
ID-3: /home size: 1.82 TiB used: 291.27 GiB (15.6%) fs: btrfs
dev: /dev/nvme0n1p2
ID-4: /var/log size: 1.82 TiB used: 291.27 GiB (15.6%) fs: btrfs
dev: /dev/nvme0n1p2
ID-5: /var/tmp size: 1.82 TiB used: 291.27 GiB (15.6%) fs: btrfs
dev: /dev/nvme0n1p2
Swap:
ID-1: swap-1 type: zram size: 31.25 GiB used: 2 MiB (0.0%) dev: /dev/zram0
Sensors:
System Temperatures: cpu: 40.0 C mobo: 31.0 C gpu: amdgpu temp: 46.0 C
Fan Speeds (rpm): cpu: 1824 case-1: 586 case-2: 0 case-3: 0 gpu: amdgpu
fan: 0
Info:
Memory: total: 32 GiB available: 31.25 GiB used: 4.06 GiB (13.0%)
Processes: 396 Uptime: 17m Shell: fish inxi: 3.3.40
May 27 11:15:11 cachyos-x8664 sudo[2404]: pam_unix(sudo:auth): conversation failed [cite: 1]
May 27 11:15:11 cachyos-x8664 sudo[2404]: pam_unix(sudo:auth): auth could not identify password for [<username>] [cite: 1]
May 27 11:15:11 cachyos-x8664 sudo[2404]: <username> : 1 incorrect password attempt ; TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/pacman --color always -Syu [cite: 1, 2]
May 27 11:17:22 cachyos-x8664 sudo[3557]: pam_unix(sudo:auth): conversation failed [cite: 2]
May 27 11:17:22 cachyos-x8664 sudo[3557]: pam_unix(sudo:auth): auth could not identify password for [<username>] [cite: 2]
May 27 11:17:22 cachyos-x8664 sudo[3557]: <username> : 1 incorrect password attempt ; TTY=pts/4 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/ls [cite: 2, 3]
May 27 11:20:53 cachyos-x8664 sudo[4155]: pam_unix(sudo:auth): conversation failed [cite: 3]
May 27 11:20:53 cachyos-x8664 sudo[4155]: pam_unix(sudo:auth): auth could not identify password for [<username>] [cite: 3]
May 27 11:20:53 cachyos-x8664 sudo[4155]: <username> : 2 incorrect password attempts ; TTY=pts/2 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/ls /root [cite: 3, 4]
May 27 11:20:57 cachyos-x8664 sudo[4746]: <username> : TTY=pts/3 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/ls /root [cite: 4, 5]
May 27 11:20:57 cachyos-x8664 sudo[4746]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 5]
May 27 11:20:57 cachyos-x8664 sudo[4746]: pam_unix(sudo:session): session closed for user root [cite: 5]
May 27 11:21:43 cachyos-x8664 sudo[5356]: <username> : TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/pacman --color always -Syu [cite: 5, 6]
May 27 11:21:43 cachyos-x8664 sudo[5356]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 6]
May 27 11:21:52 cachyos-x8664 sudo[5356]: pam_unix(sudo:session): session closed for user root [cite: 6]
May 27 11:21:54 cachyos-x8664 sudo[9725]: <username> : TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/pacman --color always -Rns cargo-c cmake meson nasm [cite: 6, 7]
May 27 11:21:54 cachyos-x8664 sudo[9725]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 7]
May 27 11:21:58 cachyos-x8664 sudo[9725]: pam_unix(sudo:session): session closed for user root [cite: 7]
May 27 11:22:00 cachyos-x8664 sudo[11738]: <username> : TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/paccache -ruk0 [cite: 7, 8]
May 27 11:22:00 cachyos-x8664 sudo[11738]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 8]
May 27 11:22:00 cachyos-x8664 sudo[11738]: pam_unix(sudo:session): session closed for user root [cite: 8]
May 27 11:22:00 cachyos-x8664 sudo[11827]: <username> : TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/checkservices -F -P -R -i gdm.service -i plasmalogin.service -i sddm.service -i lightdm.service -i lxdm.service -i slim.service -i xdm.service -i greetd.service -i nodm.service -i ly.service -i lemurs.service [cite: 8, 9]
May 27 11:22:00 cachyos-x8664 sudo[11827]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 9]
May 27 11:22:01 cachyos-x8664 sudo[11827]: pam_unix(sudo:session): session closed for user root [cite: 9]
May 27 11:22:09 cachyos-x8664 sudo[12183]: <username> : TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/systemctl restart wpa_supplicant.service [cite: 9, 10]
May 27 11:22:09 cachyos-x8664 sudo[12183]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 10]
May 27 11:22:09 cachyos-x8664 sudo[12183]: pam_unix(sudo:session): session closed for user root [cite: 10]
May 27 11:24:44 cachyos-x8664 sudo[12512]: root : TTY=pts/0 ; PWD=/root ; USER=root ; COMMAND=/usr/bin/ls /root [cite: 10, 11]
May 27 11:24:44 cachyos-x8664 sudo[12512]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=0) [cite: 11]
May 27 11:24:44 cachyos-x8664 sudo[12512]: pam_unix(sudo:session): session closed for user root [cite: 11]
May 27 11:26:22 cachyos-x8664 sudo[12735]: <username> : TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/ls /root [cite: 11, 12]
May 27 11:26:22 cachyos-x8664 sudo[12735]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 12]
May 27 11:26:22 cachyos-x8664 sudo[12735]: pam_unix(sudo:session): session closed for user root [cite: 12]
May 27 11:27:58 cachyos-x8664 sudo[17267]: <username> : TTY=pts/0 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/ls /root [cite: 12, 13]
May 27 11:27:58 cachyos-x8664 sudo[17267]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 13]
May 27 11:27:58 cachyos-x8664 sudo[17267]: pam_unix(sudo:session): session closed for user root [cite: 13]
May 27 11:30:00 cachyos-x8664 sudo[17556]: <username> : TTY=pts/2 ; PWD=/home/<username> ; USER=root ; COMMAND=/usr/bin/ls /root [cite: 13, 14]
May 27 11:30:00 cachyos-x8664 sudo[17556]: pam_unix(sudo:session): session opened for user root(uid=0) by <username>(uid=1000) [cite: 14]
May 27 11:30:00 cachyos-x8664 sudo[17556]: pam_unix(sudo:session): session closed for user root [cite: 14]
tried to edit out some info so I don’t doxx myself.
check the permissions of the sudo binary:
ls -l /usr/bin/sudo
It should look like this:
-rwsr-xr-x 1 root root … /usr/bin/sudo
check the permissions of the sudoers file:
ls -l /etc/sudoers
It should look like this:
-r--r----- 1 root root …/etc/sudoers
Check if the Account is Locked (PAM Faillock), it can happen when you type the password wrong too many times.
faillock --user username
if it shows failures you can reset with:
faillock --user username --reset
Check if the user is in the suders group:
groups username
I trust what Invisiblerasta says.
In addition…
I used to sometimes get similar issues on Manjaro XFCE if I tried changing my passphrase too many times without carefully logging out and rebooting in between changes.
The preventative fix, for me, was to ALWAYS immediately log out and shutdown cold after each change to passphrase. No other activities whatsoever. After adopting this protocol, I stopped getting issues.
It seems like there’s some normal lag between what the terminal “knows” and what the system “knows” until after a full logout/shutdown/reboot/relogin
Good Luck.
Again, go with what Invisiblerasta said for a repair attempt.
zymotek 4
su and sudo do not use the same password.
To switch user (su), you enter the password of the target user (root, in this case), because you’re logging in as that user.
To run something via sudo, you enter your own user password, because you’re elevating your own privileges, having previously been granted permission to use sudo.
Typically, on a home PC setup, people tend to use the same password for both (there’s a checkbox for that in installer). This can lead to some confusion if you then later change the root password. You’ve always been using your own password for sudo and root’s password for su, they just happened to be the same string before.
I tried all that, and it still didn’t work. I ended up having to reinstall the operating system since I couldn’t mount my drives or do anything that required a password.
Also, something else I noticed, and it seems to be happening only with Plasma, is that when I go into the UEFI BIOS boot menu, everything is overscaled and green. But once I booted into the CachyOS installer, that went away.
I tried to do everything differently in this install. I used GRUB, formatted my system drive as Ext4, and picked XFCE. So far, I haven’t had any issues that are so bad they destroy my system’s ability to work.
Gramrock 6
I have the same issue, sometimes, feels pretty random, CachyOS simply stops accepting my sudo password, i change it to something else, it says successfull, then when trying whatever iw anted again it rejects the password again, i can however enter root, so its 100% not the password.
here’s the log: 1d90a6b