I checked the links that I follow the instructions and have set up the “Manage Source” correctly.
I found a message from the output.
System.Activities.Metadata 6.0.0-20220831.1 depends on UiPath.Workflow (>= 6.0.0-20220121-04) but UiPath.Workflow 6.0.0-20220121-04 was not found. An approximate best match of UiPath.Workflow 6.0.0-20220401-03 was resolved.
What the difference is the target framework is 4.6.1, but it is automatically changed to .Net 6. Should I use VS2019 instead of VS2022 ?
I found the package generated could be found for the compatibility - Windows (Not for Windows legacy). I believe this should be .Net 6 package. And, I cannot find the extension version 3 for .net 4.6.1.
I think if the custom activities for .net 4.6.1, we need to create the class library from scratch instead of using extension.