Event Consumer Error TypeError:'NoneType'

Hi, while trying to save Event Consumer (changing the Approval Status to Approve) I got error message

TypeError : ‘NoneType’ object is not iterable

I’m doing this on ERPNext v13.8.0 with Frappe v13.8.1. Producer site is localhost:81 and consumer site is localhost:80, the DocType I’m trying to stream is Stock Entry
I tried to find more about the error on worker error log and web error log but can’t find anything.
Any help will be much appreciated, thanks in advance

Apparently, you cannot try Event Streaming with port based multitenancy. Somehow, in the event consumer table, the port number is always dropped. In my case, the consumer site is localhost:80 . But when the process insert to event consumer table, the consumer url is only written as localhost. So, when the producer is trying to approve the subscription, it ends up looking at the wrong url and cannot find the record, hence the error TypeError : ‘NoneType’

Finally, I can try event streaming on localhost with port based multitenancy. The trick is to add “host_name” : “http://localhost:port number” on your site_config file

Hey, I was trying to have this setup on my server, does it work on with ip:port_number or can I give my domain name as well.
For multi-tenant setup can you help me with how I can find the port-number, I was unable to find it in config/nginx.conf