diff --git a/postfix/Dockerfile b/postfix/Dockerfile
index aafa2a8..793e025 100644
--- a/postfix/Dockerfile
+++ b/postfix/Dockerfile
@@ -5,11 +5,13 @@ EXPOSE 25
 RUN DEBIAN_FRONTEND=noninteractive \
     apt-get update && \
     apt-get upgrade -y
-RUN DEBIAN_FRONTEND=noninteractive \
+RUN set -x; DEBIAN_FRONTEND=noninteractive \
     apt-get install -y --purge \
     postfix \
     bsd-mailx \
-    netcat
+    netcat || \
+    sed -i 's/^myhostname = \(.*\)$/myhostname = example.com/' /etc/postfix/main.cf && \
+    apt install --fix-broken
 
 ADD entrypoint /usr/local/bin/entrypoint