Hey Paul.
It’s not that Rasa 3.0 is not working. It’s a new major version and so has a lot of breaking changes. You need to change a lot in your files, otherwise stay on 2.x.
You can read all the changes in the Changelog, especially #8868 which is related to your error cannot import name 'UnfeaturizedSlot':
Follow through on deprecation warnings for the
Domain. Most importantly this will enforce the schema of theformssection in the domain file. This further includes the removal of theUnfeaturizedSlottype.
In 2.x, UnfeaturizedSlot gave a warning that it would be deprecated in 3.0, so now is the time it happened.
Forms are another example of a breaking change, see this thread to look at the new format.
If you want to migrate to Rasa 3.0, please read the Version Migration Guide.