You install a new LiteSpeed Web Server on cPanel with a Site Owner license, but it cannot be started.

LSWS is running the latest version and latest build, so what is causing the error?

You run a license check, and it seems ok:

[root@cpanel home]# /usr/local/lsws/bin/lshttpd -V
[OK] Leased license key 1 will expire in 37 days!
2019-01-25 20:35:59.894706 [NOTICE] Memory size is: 32653128KB.

When switching to LSWS from Apache, it doesn't show the error message, but it seems the LiteSpeed processes are not being started.

/usr/local/lsws/admin/misc/cp_switch_ws.sh lsws
Detected cPanel WHM Environment
Redirecting to /bin/systemctl stop httpd.service
Apache Stopped.
httpd: no process found
Created symlink from /etc/systemd/system/lsws.service to /usr/lib/systemd/system/lshttpd.service.
Created symlink from /etc/systemd/system/multi-user.target.wants/lshttpd.service to /usr/lib/systemd/system/lshttpd.service.
[OK] lshttpd.service has been successfully installed!
--- 
metadata: 
command: configureservice
reason: Enabled monitoring for httpd.
result: 1
version: 1
Redirecting to /bin/systemctl start lsws.service
LiteSpeed started successfully.

[root@cpanel home]# ps -ef | grep httpd
root       408 27932  0 20:36 pts/1    00:00:00 grep --color=auto httpd

You check the error log:

vi /etc/apache2/logs/error_log

2019-01-25 20:36:38.214024 [WARN] Domain limit has been reached, domain limit: 5, total domains: 11.
2019-01-25 20:36:38.214028 [NOTICE] Domain list:
2019-01-25 20:36:38.214031 [NOTICE] #1 [domain1.com]
2019-01-25 20:36:38.214034 [NOTICE] #2 [domain2.com]
2019-01-25 20:36:38.214037 [NOTICE] #3 [domain3.com]
2019-01-25 20:36:38.214039 [NOTICE] #4 [domain4.comm]
2019-01-25 20:36:38.214042 [NOTICE] #5 [domain5.com]
2019-01-25 20:36:38.214045 [NOTICE] #6 [domain6.com]
2019-01-25 20:36:38.214048 [NOTICE] #7 [domain7.com]
2019-01-25 20:36:38.214051 [NOTICE] #8 [domain8.com]
2019-01-25 20:36:38.214054 [NOTICE] #9 [domain9.com]
2019-01-25 20:36:38.214057 [NOTICE] #10 [domain10.com]
2019-01-25 20:36:38.214060 [NOTICE] #11 [domain11.com]

The error log clearly shows Domain limit has been reached, domain limit: 5, total domains: 11. A Site Owner License has a domain limit of 5 and cannot be used on a server with more than that. If you require more top-level domains than 5, you should upgrade your license.

The 5-domain limit will be applied to all exiting top domains on the server and unfortunately, there is no way for you to define which domain to be counted towards the 5-domain limit.

You can either remove unused domains or upgrade the LiteSpeed license to overcome the 5-domain limit.