diff --git a/roles/matrix-server/templates/env/env-mailer.j2 b/roles/matrix-server/templates/env/env-mailer.j2
index 67f867e5..9cacf789 100644
--- a/roles/matrix-server/templates/env/env-mailer.j2
+++ b/roles/matrix-server/templates/env/env-mailer.j2
@@ -1,4 +1,4 @@
-MAILNAME=matrix-mailer
+MAILNAME={{ hostname_matrix }}
 {% if matrix_mailer_relay_use %}
 RELAYHOST={{ matrix_mailer_relay_host_name }}:{{ matrix_mailer_relay_host_port }}
 {% endif %}