Hello,
Your issue is not specific to Debian in any way:)
Like the error says, the command:
curl -I -v http://[myserver]/api_v3/index.php?service=system&action=ping
failed.
Does:
curl -I -v http://[myserver] work?
if not, then the host you supplied is simply not resolvable, you must supply a resolvable one or add the one you want to /etc/hosts to make it resolvable.
Note that the same needs to happen from whereever you plan to run the browser talking to the Kaltura web I/Fs.
if it is resolvable and /api_v3/index.php returns a 404, what is the output for
# apachectl -t -DDUMP_VHOSTS
?