Cannot create a label Class

[JeffWhite2]

I am unable to create a label class from a layer.  I have tried right click the feature layer and selecting labeling properties.  I get what is shown in the screen shot below a pop up where I cannot select an existing or create a new class.  Nothing works on the menu.  This project was a web map (ArcGIS online) that I have opened in Pro.  The work around is to create the label class in the web map, save, then open in Pro.  This is not an efficient solution.  In pro I have also tried the labeling menu tab on the top of the screen.  When I select create a new class the menu disappears.  Does anyone know what is going on?

[DanPatterson]

Just to check that...

Ensure that List By Labeling is the active method of displaying the Contents pane. Click the List By Labeling tab List By Labeling.

Use label classes—ArcGIS Pro | Documentation

[JeffWhite2]

Tried that but thanks, List by Labeling is  selected.

[DanPatterson · Accepted solution]

That would leave the possibility that the layer you are trying to work with isn't supported because it isn't locally stored and controlled by a project file gdb.  Try copying the web layer to your project gdb and see if that is the potential issue

[JeffWhite2 · Accepted solution]

Your suggestion to copy the web layer so it's locally stored worked.  Thank you!

[CarsonG]

There appears to be a bug with creating labels for web layers when they are first added to a Pro Project sometimes from AGOL when opening a web map. I have even had layers where a label class was enabled in AGOL and when the layer is loaded into Pro, the label class is not accessible. 

Instead of storing it locally, you can copy/paste the same layer into the project then remove the problematic layer. This has allowed others and me to create label classes this way while still maintaining the connection to the hosted service.

[AmandaPutri]

Similar thing occurred when I brought our organisation's webmap from AGOL to ArcPro. I tried your suggestion by copying and paste the layer which the label setting is missing, then remove the broken one. It solved the issue! Thank you.