Are you still having issues with this? If so, just so I can best help, which version of Twinmotion are you using? Depending on you version of Twinmotion, there may be some compatibility issues. If you're using Twinmotion 2022.2.3, then you will need the 5.0.3 version of the Datasmith Exporter plugin from https://unrealstudio.epicgames.com/UnrealDatasmithRevitExporter_5_0_3_v2.msi to avoid compatibility issues. If you are using Twinmotion 2023.1.2, then you will need either version 5.1.1 or version 5.2 (recommended).
Be sure to also uninstall any previously installed plugins, as previous installation can interfere with the installation of a new plugin.
If you continue to have issues, please submit a bug report at https://twinmotionhelp.epicgames.com/s/case-community-page so our support team can assist.