diff --git a/src/freedombone-app-mailpile b/src/freedombone-app-mailpile
index ef929208..63b1c7e9 100755
--- a/src/freedombone-app-mailpile
+++ b/src/freedombone-app-mailpile
@@ -401,7 +401,7 @@ function install_mailpile {
     disable_email_encryption_at_rest
 
     # if strict https is enforced then buttons don't work. This is probably a security bug
-    sed -i "s/Content-Security-Policy/d" $mailpile_nginx_site
+    sed -i "/Content-Security-Policy/d" $mailpile_nginx_site
 
     # link to the administrator's keyring
     if [ -d /var/www/$MAILPILE_DOMAIN_NAME/mail/.gnupg ]; then