diff --git a/src/Pact/Types/Util.hs b/src/Pact/Types/Util.hs
index 919b8b5d2..acb46420e 100644
--- a/src/Pact/Types/Util.hs
+++ b/src/Pact/Types/Util.hs
@@ -348,4 +348,7 @@ base64DowngradeErrorMessage
 base64DowngradeErrorMessage
   (L.stripPrefix "invalid padding at offset: " -> Just suffix) =
       "invalid padding near offset " <> suffix
+base64DowngradeErrorMessage
+  "Base64-encoded bytestring has invalid size" =
+      "invalid base64 encoding near offset 0"
 base64DowngradeErrorMessage errMsg = errMsg