Cannot connect to the Docker daemon at unix:/var/run/docker.sock. Is the docker daemon running?

I have applied every solution available on internet but still I cannot run Docker.

I want to use Scrapy Splash on my server.

Here is history of commands I ran.

docker run -p 8050:8050 scrapinghub/splashsudo docker run -p 8050:8050 scrapinghub/splashsudo usermod -aG docker $(whoami)sudo docker run -p 8050:8050 scrapinghub/splashnewgrp dockersudo docker run -p 8050:8050 scrapinghub/splashrebootsudo docker run -p 8050:8050 scrapinghub/splashdocker run -p 8050:8050 scrapinghub/splash

You can see I tried to restart my server as well, but it didnt help.

see output of ps -aux | grep docker

root@mani:/var/www/html# ps aux | grep dockerroot      8524  0.0  0.8 127904 13964 ?        Ssl  17:21   0:00 /usr/bin/dockerd --raw-logsroot      8534  0.0  0.3  90588  5012 ?        Ssl  17:21   0:00 docker-containerd -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --metrics-interval=0 --start-timeout 2m --state-dir /var/run/docker/libcontainerd/containerd --shim docker-containerd-shim --runtime docker-runcroot      8543  0.0  0.0   8812   764 pts/1    S+   17:21   0:00 grep --color=auto dockerroot     16356  0.0  0.0  17200   964 pts/1    S    17:14   0:00 newgrp dockerroot     20080  0.0  0.0  17200   964 pts/1    S    17:06   0:00 newgrp dockerroot     30221  0.0  0.0  17200   964 pts/1    S    17:09   0:00 newgrp docker

but it gives the error:

Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.