Data Platform:

On Admin UI --> Click the "?" icon which will open a new window with the Normalize Help menu.
Under Contents look for --> Support tool-Data platform --> Download Diagnostic Data.

Select the relevant logs/data you need to extract.

User Console:

At the top right on User Console UI, click your account name:
Click User Console Help --> Under the BDNA User Console Basics --> Select 'Download Diagnostic Data'.

Each of these have a 'Standard' and 'Advanced' section to download relevant logs.
You can attach to these to a support case for a Support Engineer to review.