OPC UA PubSub Configuration Error (PLCN0039): '...': The specified data set does not exist in the current configuration.
In the configuration of the OPC UA PubSub communication, a data set is selected in the properties editor of a writer which is not defined in the configuration.
Possibly, you have renamed a data set (under 'Published data sets') after it has already been selected for a writer.
Remedy
Open the properties editor of the affected writer and select an available data set from the drop-down list. Alternatively, give the data set its original name by renaming it again.
Example