I have connected Siemens Panel OPC UA Server, but I get only uncertain LastKnownvalue read.
Max per Operation reduced to 64, I tried 300, 500 as well...(this helped me in few cases before BTW).
The HMI is behind NAT router (this is the reason why the captures protocol is TCP, and not opcua)
Host Override option used.
UA Expert connected and read values, no issues.
Attached Wireshark traces.
I guess easy job for @Kevin.Herron. 
opcua_00001_20231221102537.zip (3.8 MB)
What is the IP used to connect to the server you are troubleshooting?
Another capture where you do an edit/save on the connection would be useful so that creation of Subscriptions and Monitored Items is captured. From the problem description it just sounds like the items are not successfully created or they are created but no values are reported by the server.
IP address used: 192.168.36.33 (NAT to 192.168.3.200 - the HMI static IP address).
Yes, Kevin, correct, I can browse the tags in Quick Client, but no values are read.
opcua_connection_enabled_00001_20231221112759.zip (3.8 MB)
Are there any errors in the Ignition logs? Can you upload them?
I suspect you're running into this same issue based on the capture: Unable to browse tags using Siemens WinCC v 15 - #13 by Kevin.Herron
If you can't upgrade/fix the server software then as a workaround you might be able to use a dedicated Tag Group set to OPC Read Mode for tags from this server and any others like it.
Thank you, Kevin, but I tried with read only tags and could not read any values. Unless if I did not understand your point.
I'm not sure this is what I was suggesting...
I finally had a word with the software guy who has configured the OPC UA Server in the factory.
Will be checked once again tomorrow. There is a probability the server has not being activated at all, just configured. Do not know if in that case I would be able to connect at all. Thank you, @Kevin.Herron Kevin for the tag group suggestion , will have that in mind.
Just to close the thread, the server was not activated indeed. All good now.