The Nexus Repository Manager does not start

I installed the latest version Nexus 3.21.1-01 on my Centos7 server under the user root.

After reading the help document ’ Run as a Service’, I created a new user ‘nexus’ and change the bin/nexus.rc file to run_as_user="nexus".

And then I also change the configuration like the article to let nexus run as a service.

Now when I want to start the nexus using command ‘nexus start’, the server can not start like the following:
nexus

I google the whole website but do not find the answers.

Any help will be preciated!

Have a look here… this might be the problem:

https://help.sonatype.com/display/NXRM3/Run+as+a+Service#RunasaService-PIDFile