diff --git a/src/cloudron.js b/src/cloudron.js
index 3c34f2026..7eed7fbe3 100644
--- a/src/cloudron.js
+++ b/src/cloudron.js
@@ -251,6 +251,8 @@ function prepareDashboardDomain(domain, auditSource, callback) {
 
     debug(`prepareDashboardDomain: ${domain}`);
 
+    if (settings.isDemo()) return callback(new BoxError(BoxError.CONFLICT, 'Not allowed in demo mode'));
+
     domains.get(domain, function (error, domainObject) {
         if (error) return callback(error);
 
@@ -308,6 +310,8 @@ function setDashboardAndMailDomain(domain, auditSource, callback) {
 
     debug(`setDashboardAndMailDomain: ${domain}`);
 
+    if (settings.isDemo()) return callback(new BoxError(BoxError.CONFLICT, 'Not allowed in demo mode'));
+
     setDashboardDomain(domain, auditSource, function (error) {
         if (error) return callback(error);
 
diff --git a/src/domains.js b/src/domains.js
index 5a31be361..fd628edd0 100644
--- a/src/domains.js
+++ b/src/domains.js
@@ -253,6 +253,8 @@ function update(domain, data, auditSource, callback) {
 
     let { zoneName, provider, config, fallbackCertificate, tlsConfig } = data;
 
+    if (settings.isDemo() && (domain === settings.adminDomain())) return callback(new BoxError(BoxError.CONFLICT, 'Not allowed in demo mode'));
+
     domaindb.get(domain, function (error, domainObject) {
         if (error) return callback(error);