ssh default password not working on raspberry pi 4

I installed DietPi_RPi-ARMv8-Buster on the new raspberry pi 4. Changed the dietpi.txt and dietpi-wifi.txt with required settings and then tried to SSH into the pi but always gives me
Permission denied, please try again.

i tried it with ssh root@ip and ssh dietpi@ip the result is the same. I also checked the dietpi.txt again and I found that

AUTO_SETUP_GLOBAL_PASSWORD=dietpi

and this is exactly the password I was entering still I was not let in.
Any one facing the same issue?

Hi,

did you tried to reflash the image and boot the first time without any configuration change done?