diff --git a/go.mod b/go.mod
index 018109c..13b5d02 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@ require (
 	github.com/emersion/go-smtp v0.21.3
 	github.com/go-ozzo/ozzo-validation/v4 v4.3.0
 	github.com/kelseyhightower/envconfig v1.4.0
-	github.com/mailgun/mailgun-go/v4 v4.15.0
+	github.com/mailgun/mailgun-go/v4 v4.15.1
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.20.3
 	github.com/sirupsen/logrus v1.9.3
diff --git a/go.sum b/go.sum
index b242eea..18dadf0 100644
--- a/go.sum
+++ b/go.sum
@@ -40,8 +40,8 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
-github.com/mailgun/mailgun-go/v4 v4.15.0 h1:3NQU0r2XItJbyIZ21iBI9ps0+vPIMoGyI2XK7ZTN/DQ=
-github.com/mailgun/mailgun-go/v4 v4.15.0/go.mod h1:L9s941Lgk7iB3TgywTPz074pK2Ekkg4kgbnAaAyJ2z8=
+github.com/mailgun/mailgun-go/v4 v4.15.1 h1:/xL/JBF/SWd3m9iscO1wKpv9tzcK21eRRJAqIlyk3EQ=
+github.com/mailgun/mailgun-go/v4 v4.15.1/go.mod h1:L9s941Lgk7iB3TgywTPz074pK2Ekkg4kgbnAaAyJ2z8=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=