To allow OPC UA clients to connect to Ignition's UA server and access MQTT Engine tags, you will need to enable the Expose Tag Providers property of the Ignition OPC UA Server Settings.
When enabled, Ignition Tag Providers will be exposed through the UA server allowing third-party UA clients to access tags in the provider.
Settings for the Ignition OPC UA Server can be found under the Config section of the Gateway's web interface. On the sidebar, locate OPC UA > Server Settings.
Select the checkbox to Show advanced properties

Select the checkbox to enable Expose Tag Providers and Save Changes
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