I can't login to DirectAdmin on port 2222 [DirectAdmin]

If you are unable to access your server via http://1.2.3.4:2222, then 1 of 3 things is likely happening:

1. DirectAdmin might not be running or
2. You have a firewall blocking port 2222.

Number 2. is easy to check by simply running (only on redhat systems):

Then test directadmin again.

If that didn't fix it, then you'd need to check your /var/log/directadmin/error.log to check for any errors as to why it isn't starting:
 

Common problems are:

1. Incorrect ethernet_dev set in the /usr/local/directadmin/conf/directadmin.conf file.
2. Invalid license, either due to wrong uid/lid, IP, or date. Try: Updating your DirectAdmin License Manually
3. Binaries for a different operating system.

You can always try running DirectAdmin by hand (if it's not already running) to see what the problem is.
 

to start it in the terminal with debug level 200. Use Ctrl-C to stop.