I am currently using Houdini Indie version.

I tried to reder all in VAT node by choosing RBD dynamic mode, and wanted to run in UE4.26.
However, it doesn't properly work in UE4.26.
What can I do?

Hey, you can check out this guide. There is a slide on Debugging. (If you download the PDF version, it's text-searchable.) It documented the most common 5 ways to debug your scene. Also remember to cache your sim before loading it to VAT, that also helps.

https://www.artstation.com/artwork/zOyke6 [www.artstation.com]