Getting "400: Bad request" for RTF to PDF

Hi,
I’m using the groupdocs-conversion-cloud, version 21.12.
I’m receiving 400 Bad request with no additional info when trying to convert from RTF to PDF.
The same request works when I change the format to DOC.
I get the same error converting to PDF from TSV, MPP and TAB files as well.

What might be wrong with the request?
Can I get a more informative error somehow?

@evgenykr

Please check the error details from API usage logs from groupdocs.cloud dashboard. Otherwise, share your sample code and document with us. We will investigate the issue and will guide you accordingly.