I found a strange bug, when my domain has 0 in name for example i0io, the first one is zero not O, I can not add subdomains to this domain:
Error message: Invalid domain.
Is there reason why?
Provider: Digital Ocean
System: Ubuntu 18.04
OLS or Enterprise?
OLS version 1.9 build 4E
Installing from official server or mirror server?
official
Install Memcached extension for PHP?
no
Install LiteSpeed Memcached?
yes
Install Memcached?
no
Install Redis extension for PHP?
yes
Install Redis?
yes
Thanks! It works after update 
nice 