Navigate to 'Workspace Catalogs/Palettes/' and drag and drop the tool palette into AutoCAD Architecture or MEP.Navigate to the file that says 'Workspace Catalogs' and drag and drop the catalog into the Content Browser Catalog area in AutoCAD Architecture or MEP.Navigate to the folder that says 'Tool Palettes' and select the custom tool palette and drag and drop it into the AutoCAD Architecture or MEP tool palettes.
Try one or more of the following solutions to attempt to fix your issue: Use the Content Browser to add your AutoCAD tool palettes to AutoCAD Architecture or AutoCAD MEP: