diff --git a/build-constraints.yaml b/build-constraints.yaml
index c3c7a827..a5a0ba86 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -5715,6 +5715,7 @@ expected-test-failures:
     - doctest-discover # 0.1.0.9 https://github.com/karun012/doctest-discover/issues/22
     - doctest
     - reanimate-svg # https://github.com/commercialhaskell/stackage/issues/5688
+    - wai-saml2 # https://github.com/mbg/wai-saml2/issues/4
 
     # Assertion failures, these can be real bugs or just limitations
     # in the test cases.