## What this teaches
How to unknownError adding a strategy via API on 5.0.0: upgrade to 5.0.1.
## The problem
Issue Unleash/unleash#3640 (closed, 13 comments): Adding a new strategy to a feature via POST /projects/:projectId/features/:featureName/environments/:environment/strategies on Unleash v5.0.0 returns UnknownError: Cannot read properties of undefined (reading 'name').
## What worked (verified answer)
On Unleash 5.0.0, adding a strategy via the API returns a cryptic UnknownError instead of the real problem because the 5.0 error-body work missed this endpoint. Fix: upgrade to 5.0.1, which returns a proper error message (a 404 explaining what's actually wrong). If you see the UnknownError, upgrade and read the real error before debugging your request.
## Source
gh:Unleash/unleash#3640 - https://github.com/Unleash/unleash/issues/3640