diff --git a/smtp-relay.sh b/smtp-relay.sh
index e4d9bdb..8632f6e 100755
--- a/smtp-relay.sh
+++ b/smtp-relay.sh
@@ -10,9 +10,8 @@ SMTP_TLS_SECURITY_LEVEL=${SMTP_TLS_SECURITY_LEVEL?Missing env var SMTP_TLS_SECUR
 
 
 # handle sasl
-echo "${SMTP_RELAY_HOST} ${SMTP_RELAY_USERNAME}:${SMTP_RELAY_PASSWORD}" > /etc/postfix/sasl_passwd || exit 1
+[ -w /etc/postfix/sasl_passwd ] && echo "${SMTP_RELAY_HOST} ${SMTP_RELAY_USERNAME}:${SMTP_RELAY_PASSWORD}" > /etc/postfix/sasl_passwd || exit 1
 postmap /etc/postfix/sasl_passwd || exit 1
-rm /etc/postfix/sasl_passwd || exit 1
 
 postconf 'smtp_sasl_auth_enable = yes' || exit 1
 postconf 'smtp_sasl_password_maps = lmdb:/etc/postfix/sasl_passwd' || exit 1