Hi Joseph,
Digging a bit more it seems that the RenderWebBlock is not bullet proof: https://www.outsystems.com/forums/discussion/14097/render-webblock-html/
So, could you try another thing:
- Place your block inside a screen that has the same theme as your emails.
- Then, you use GetRequest_Submit (from HttpRequestHandler) to get the html (in the TextContent output)
Let me know if it works.
Cheers,
José