diff --git a/build-constraints.yaml b/build-constraints.yaml
index 8a3da9f6..73128497 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -9252,6 +9252,7 @@ expected-test-failures:
     - sydtest-wai # epollControl does not exist. Stackage server issue?
     - users-persistent # sqlite
     - users-postgresql-simple # PostgreSQL
+    - yesod-core
     - wai-cors # PhantomJS
     - wai-middleware-delegate # Access to httpbin.org is unreliable (at the moment 504 Gateway Time-out).
     - wai-rate-limit-redis # Redis