diff --git a/build-constraints.yaml b/build-constraints.yaml
index 6f4475f5..a600bfb9 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4384,6 +4384,9 @@ packages:
         - req < 2.0.0
         - retry < 0.8.0.0
 
+        # https://github.com/commercialhaskell/stackage/issues/4346
+        - servant-blaze < 0.9
+
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of