I’m able to login with my password and even install something with “yay”. However whenever I try to install something else or do anything else that requires password it no longer works. I restart and the same thing happens. Able to login, first attempt at something works. Then password no longer works.
And yes I’ve tried resetting the password but it requires the old password which still doesn’t work… 
i’m confused:
doesn’t yay ask for your password when you use it to install something?
Well, but just a shot in the dark. Maybe a keyboard layout issue. Your desktop environment is set to another layout than your display/login manager. So you can login, but with the layout being different afterwards, you are not typing what you think you are 
After rebooting 2 more times it seems to be working again. I dont see any issues with the keyboard layout. If anyone has any additional input on this in case it happens again. Please comment. Thanks.
as i said - it was just a shot in the dark… can be problematic when using special characters for your password and the keyboard layout is different.
Anyway - glad its working for you now.
If this happens again, check the output of faillock - it’s possible you’re trying the password incorrectly and locking yourself out?
I found this thread because I had this issue today. After booting up my laptop I did sudo pacman -Syu and it worked fine. There were no updates available. I just closed the terminal emulator. After few minutes (I think more than 15 in this case) I tried to run another command with sudo, it asked me for my password again and the response was “Sorry, try again.” I thought that I had caps-lock on or something like that, but no. Keyboard layout was also fine and I even tried typing my password in text editor to check that and it was okay. I did it 3 times “wrong”.
What I did to unlock myself.
faillock - it shows me that I put wrong password 3 timesfaillock --reset - to unlock itfailock - I run it again to confirm that there is no info about mistype password right nowStill don’t know… but I’m like 99% sure that I was typing my password correct from the beginning.
I kept having to reboot when it would happen. An unrelated issue came up with my dual boot so I ended up reinstalling it, I have not run into the issue since. I know this doesn’t help but that’s where I ended up.
This happens to me too. Usually login in and out solves it too.
I never had this issue again since then but today I found another report about it in r/archlinux
Wondering, are you guys using gnome DE?
In January I had a problem in manjaro were after suspend I could not login to my session anymore. It just wouldnt pick up my password. Maybe totally unrelated but very strange bug.
A suggestion, could you try an alternative terminal shell, just install another to try?
Yes. I use GNOME. Actually it was only one time issue and never happened again to me.
BTW, after some research I found similar posts about it from years '12, '17 in Arch Linux forum. In one case somebody had problem because of corrupted /etc/sudoers file, but in another it was related to something called “pam/pambase” and reinstalling this thing was a solution. In the reddit link I posted above there is also something related to “pam/pambase” errors from journal.
For now, everything is OK and I don’t feel confident enough to mess around these things until absolutely necessary.
Old posts from Arch Linux forum which I found:
https://bbs.archlinux.org/viewtopic.php?id=142720
https://bbs.archlinux.org/viewtopic.php?id=142941
https://bbs.archlinux.org/viewtopic.php?id=143487
https://bbs.archlinux.org/viewtopic.php?id=142729