Mac osx Ventura 13.1 - Safari fails to connect to localhost server on port 8889 (localhost:8889)

The Safari browser on my MacBook Pro successfully connects to http://localhost/. However, Safari has now stopped connecting to a local web server located at

http://localhost:8889/tree?token=1d47dc1997e32bff43e96eeb547399a20805f134f22c6b60

which hosts a Jupyter notebook for python/ sagemath (https://jupyter.org/).

Previously, I had been running Jupyter notebooks on Monterey for many months. However, after Monterey on my Macbook Pro required a reboot, Safari stopped working and was unable to connect to localhost:8889. Hence, I upgraded to Ventura to access the latest version of mac osx and in the hope that the localhost:8889 error might be rectified. However, it remains.

I have googled this error and tested many suggested fixes (updates to httpd.conf etc) without success. Any help would be greatly appreciated.

Regards,

Joe Young