Arduino connection with the server failed
I don't know of this library, but you're using the connection code twice, once in the setup() and later again in the loop().

You're already checking whether the client exists:

if (client) {


Why are you asking a few lines down again to connect?

if (client.connect(server, 80)) {


My guess is, that this if()-Clause is not necessary. Or the connection in the setup() should be removed.

If this isn't the source of the error, first test whether the server on 192.168.0.11 is running and that you can connect (from a different device) to the port 80.