Misleading message when there's no connection to the server,

An additional check is required whether the server is accessible. Currently, it just blindly tries each of the API requests:

```
2024/02/06 09:59:30 Failed to create domain due to: Get "http://10.0.35.120:8080/client/api/?apiKey=LIN6rqXuaJwMPfGYFh13qDwYz5VNNz1J2J6qIOWcd3oLQOq0WtD4CwRundBL6rzXToa3lQOC_vKjI3nkHtiD8Q&command=createDomain&name=Domain-PIcJCkazXi&parentdomainid=7e12782c-c3fb-11ee-bcc6-1e002000040b&response=json&signature=o0uRUi7kQ4nOABlxYWO%2F8o1CtB0%3D": dial tcp 10.0.35.120:8080: connect: connection refused
2024/02/06 09:59:30 Failed to create domain due to: Get "http://10.0.35.120:8080/client/api/?apiKey=LIN6rqXuaJwMPfGYFh13qDwYz5VNNz1J2J6qIOWcd3oLQOq0WtD4CwRundBL6rzXToa3lQOC_vKjI3nkHtiD8Q&command=createDomain&name=Domain-yJniRGHGlc&parentdomainid=7e12782c-c3fb-11ee-bcc6-1e002000040b&response=json&signature=cKe2Ql3yDSTioi478FFnFLm0BHY%3D": dial tcp 10.0.35.120:8080: connect: connection refused
```

and even though these are failing, it reports this:

```
time="2024-02-06T09:59:30+02:00" level=info msg="Created 1000 domains in 2.21 seconds"
```

Note: The final table is showing the proper result:

```
+---------------------+-------+-------+-------+-------+--------+-----------------+-----------------+-----------------+
| TYPE | COUNT | MIN | MAX | AVG | MEDIAN | 90TH PERCENTILE | 95TH PERCENTILE | 99TH PERCENTILE |
+---------------------+-------+-------+-------+-------+--------+-----------------+-----------------+-----------------+
| domain - All | 1000 | 0.002 | 0.022 | 0.004 | 0.003 | 0.007 | 0.009 | 0.015 |
| domain - Successful | 0 | NaN | NaN | NaN | NaN | NaN | NaN | NaN |
| domain - Failed | 1000 | 0.002 | 0.022 | 0.004 | 0.003 | 0.007 | 0.009 | 0.015 |
+---------------------+-------+-------+-------+-------+--------+-----------------+-----------------+-----------------+
```