TC server would try to connect to internet to validate the runtime, in an offline environment it would fail.
In such case, you should disable the on-demand runtime download feature.
Under
`pivotal-tc-server-4/standard-<version>.RELEASE/conf/tcserver.properties`, uncomment the
`runtimes.ondemand` line and set the value to
`false`, the result should look like below:
# runtimes.ondemand=<value>
# Specifies whether to use the tc Server Runtime Repository to automatically download a
# runtime if not found locally. This feature requires internet access.
# Note: This feature will not work when the JVM version running tcserver is less than 8
#
# Default: true
runtimes.ondemand=false