how to re-install portainer docker?

I made a site with docker very long time ago but I lost the password of portainer. So, I try to re-install to reset my Id and password, but it seems portainer keep containing my previous Id and password. I delete volume but is still not working.I did like this.

step1. stop and delete container.

$sudo docker ps -a (to check container list)$sudo docker stop [container ID]$docker rm -v [container ID]

step2. delete image

$docker images (to check image ID)$docker rmi [image ID]

step3. delete volume

$docker volume rm portainer_data

step4. re-install portainer

$docker run -d -p 9000:9000 --name portainer --restart always -v /var/run/docker.sock:/var/run/docker.sock -v/data/portainer/data:/data portainer/portainer

when I try to access to portainer, still asking last ID and password.