Sorry to hear you had some issues with that. I’m not sure what version you upgraded from but there were some breaking changes in recent releases (4.7.8) meaning you need to have at least Java 9 running to use version all versions since then including 4.8.5. There were other breaking changes that would affect 4.8.5 as well so please check here.
Once you looked into that, we usually suggest you look at the potential firewalls which it sounds like you did already. We also ask that you do not use the same port for the Engine server that you do for Engine Admin. If you already made sure of that too well then the same rule goes for SSL config. Set that up on its own port too like port 443.
I have seen it where there were other applications running in the background on 8088 and already in use that the customer was not aware of.
We nay need a support ticket to investigate further, but this is usually what we suggest below for people who see that error: connection refused for port 8088:
Can you ensure that you don’t have any firewalls running that may block access to the following Wowza ports (open in both directions)
RTMP/RTMPT/RTMPE/RTSP(interleaved) Streaming TCP 1935
RTP UDP Streaming UDP 6970-9999
JMX/JConsole Monitoring and Administration TCP 8084-8085
If there isn’t any firewall then you can try testing if Wowza is running. Enter the following in your browser
If it returns a version number then that should show that Wowza Streaming Engine is running.
This is the Wowza Streaming Engine Manager process (which you seem to have the issue with). See if it opens when you use the IP address of the server.