Cannot connect to Katalon Server. Make sure you have started Recorder on Katalon Studio


I’m going through the very strange issue which I cannot solve for days. I’m running Katalon Studio on Mac (Sierra) and every time when I start the record of actions I face the pop up message saying that: “Cannot connect to Katalon Server. Make sure you have started Recorder on Katalon Studio”. I double-checked and I started the recorder so I’m very confused about how to make it work. Being connected to another office network in different city I managed somehow to record some actions (also wondered why it asked me for activation of the product once again), but now I’m back to my initial network and this problem occurs again. I don’t understand why it depends on it? Shouldn’t the recorder work without any additional configurations of proxy, should it? I would greatly appreciate someone’s assistance as I really like the tool but unable to use it because of such a strage issue.

Thanks in advance to everyone!
Kind regards,

Ok, so I’m new at Mac however found the content of hosts file a bit suspicious and thus compared the original hosts file with the one I have and it’s somewhat different. So I copied the genuine content of hosts file:
## # Host Database # # # localhost is used to configure the lookback interface # when the system is booting. Do not change this entry. ## localhost broadcasthost ::1 localhost fe80::1%lo0 localhost

and restarted Mac. Now everything is working fine so the issue can be closed.

Big thanks to all!

Yep, and this is the only record I have there:

“ localhost”

Firewall is off and was not operating at all. The log file is gigantic hence unfortunately I cannot find the lines related to my issue

Although, I think the last ones that appeared right now may be connected with the problem:

Jun 20, 2017 1:25:32 PM org.apache.http.impl.execchain.RetryExec execute
INFO: I/O exception (org.apache.http.NoHttpResponseException) caught when processing request to {}-> The target server failed to respond
Jun 20, 2017 1:25:32 PM org.apache.http.impl.execchain.RetryExec execute
INFO: Retrying request to {}->

But if so, than I have to check the localhost config, don’t I?

Is there any Firewall rules which is blocking the connection between recorder/spy and Katalon Studio? For the logs, you can find it on Mac by:

  • Click on ‘Katalon Studio’ menu -> Select About Katalon Studio item

  • Select ‘Installation Details’ -> ‘View Error Log’ item.

Hi Hanh,

Thanks for prompt reply.

I’m using the “New browser” option and it’s Firefox.

Here are some screenshots on your demand:
1. I’m starting the record:

2. Receiving the error:

3. Cheking the toggle on Firefox Extention and the port (am not certain if it’s correct as it was applied automatically and it is sort of dynamic (different for every session)):

4. Cheking logs on Mac (not found):
Could you please advice where can I find the logs if runnign on Mac?


  • Which option you’ve chosen from our recorder? Is it ‘Active Browser’ or ‘New Browser’?

  • Do you have any screenshot showing your issue at that time?

  • Any logs from your side will be helpful also, you can find Katalon Studio logs in .metadata folder, e.g: C:\4.6.0\Katalon_Studio Windows_64-4.6\config\.metadata\.log