diff --git a/build-constraints.yaml b/build-constraints.yaml
index c88ac3de..5db1f3c3 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -2157,7 +2157,7 @@ packages:
         - monad-logger-prefix
         - monad-metrics
         # - ekg-cloudwatch # http-conduit 2.3 via amazonka
-        - smtp-mail
+        - smtp-mail < 0 # https://github.com/jhickner/smtp-mail/issues/24#issuecomment-499601949
         - liboath-hs
         - servant-quickcheck < 0
         - esqueleto