Although this issue has been around for quite some time and discussed in a post from July 24, I ran into the same issue in the past few days and it took quite a bit of searching to locate any information. So I thought I would do a follow-up with a different solution.
The original post (that I found) is here.
The solution proposed in this post didn’t work for me because when I ran the openssl command, the -6 option wasn’t supported. When I removed the -6, a password hash was created but it did not work. It also looked too short. The -1 option was used which was supported and the hash looked a better size but again didn’t work.
I was using RPiImager v1.85 and the ASL arm64 image v3.0.16 with a Raspberry Pi4b.
6-7 images were burned to the SD card but all produced the same result. I tried serveral username / password combos including leaving the default.
I had a laptop to hand that had just been set-up with a fresh copy of Windows 10 using the Microsoft Media creation tools. Again using this laptop with the same version of the RPiImager and ASL image I could not login using PuTTY or the web interface when the RPi was booted.
I searched my download directory and located an older copy of the RPiImager. v1.62.
This version does not have as much flexibility when editing the settings before burning the image to the SD card. i.e. Picking a username and password.
Instead, you have to stick with pi as the user name but you can choose your own password.
Hey presto… this worked and I was able to login to ASL 3 via the Web interface and with Putty via SSH.
Tom - G0JSV