It has been noticed that till FNP-11.16.4, the lmadmin installation on Windows Server 2019 (and Windows Server 2016) fails with an error as ""Installer User Interface Mode Not Supported"".
We have been able to root cause this reported ambiguity with Java installation and the culprit is the Java version in installation.The issue can only be seen with latest version of Java (i.e. Java 8_u221) and above.
Downgraded the java version to a lower version (v8_202,/v8_211).
This issue is alreadt reported to FNP engineering and most probably will be fixed in FNP-11.16.5 (not a commitment, so kindly check the release notes about that).