Cannot Connect Using Core Tunnel

Hello, I am trying to connect to a bastion host on AWS. Core Tunnel works fine on my Macbook and used to work fine on my IMac. Then it stopped working on my iMac and I cannot get it to connect. Even though my Macbook connects fine. I have uninstalled Core Tunnel and reinstalled the connection information is identical. The error message is could not request local forwarding. Totally stumped on this one. Thanks,

Hi John,

Could you please enable logging and send me a copy of desensitized connection log? This will help me identify the problem.

Kindly Regards,


Hi Yang,

I finally got a chance to run the log files. See attached PDF. The first log is from my Macbook which works and the second is from my iMac which did work but now has stopped working. I have highlighted the differences in the log responses on the last page. I appreciate your help with this.

Comparison Log Files.pdf (104 KB)

Thank you for the log and the comparison.

The port 5432 on your iMac was occupied, please run this command to find out which process using the port:

lsof -i:5432

To fix this problem, you can choose another port number for the local forwarding.

Kindly Regards,


Hi Yang, that worked. I just switched to a different port. Slowly getting the hang of it.

Thanks for your help!!

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