ssh not using server name in config

I try to make a config for connecting to a remote ssh server via the command ssh <server short name>. I put this into ~/.ssh/config:

Host <server short name> <server full name>
    Host <server full name>
    User <my username on the remote server>
    Port 22022
    ForwardAgent yes
    ForwardX11 yes

I can connect using

$ ssh <server full name>

but it fails with the command

$ ssh <server short name>
ssh: Could not resolve hostname <server short name>: Name or service not known

I've checked the spelling several times and I could not find a mistake. Any ideas why the second command fails?

Host is not as SSH option; it always starts a new section, regardless of indent level. Thus you have two config sections; an empty one matching <shortname> <fullname> and then one matching just <fullname>.

Instead, the second line needs to be HostName <fullname>.

See the man pages

The host keyword is used to group configuration together and can also be used to define an alias for a host or configure multiple hosts at once.

Consider the following scenario: At work you have two servers, called dev.example.com and test.example.com where you use the same key pair and a github account with a second key pair. You could then setup the following config

host *.example.com
identityfile ~/.ssh/work-key
user bob
Port 22022
ForwardAgent yes
ForwardX11 yes

host github.com
identityfile ~/.ssh/github-key

host dev
hostname dev.example.com

host test
hostname test.example.com

And the use something like this to connect:

ssh dev