diff --git a/src/app.cpp b/src/app.cpp
index 43b1c4e3..d32a5bfa 100644
--- a/src/app.cpp
+++ b/src/app.cpp
@@ -183,7 +183,7 @@ void app::tickNtpUpdate(void) {
     bool isOK = mWifi.getNtpTime();
     if (isOK || mTimestamp != 0) {
         if (mMqttReconnect && mMqttEnabled) {
-            mMqtt.tickerMinute();
+            mMqtt.tickerSecond();
             everySec(std::bind(&PubMqttType::tickerSecond, &mMqtt), "mqttS");
             everyMin(std::bind(&PubMqttType::tickerMinute, &mMqtt), "mqttM");
         }
diff --git a/src/publisher/pubMqtt.h b/src/publisher/pubMqtt.h
index df2cf0dc..a1eac878 100644
--- a/src/publisher/pubMqtt.h
+++ b/src/publisher/pubMqtt.h
@@ -59,9 +59,8 @@ class PubMqtt {
 
             if((strlen(mCfgMqtt->user) > 0) && (strlen(mCfgMqtt->pwd) > 0))
                 mClient.setCredentials(mCfgMqtt->user, mCfgMqtt->pwd);
-            char clientId[64];
-            snprintf(clientId, 64, "%s_%s-%s-%s", mDevName, WiFi.macAddress().substring(9,11).c_str(), WiFi.macAddress().substring(12,14).c_str(), WiFi.macAddress().substring(15,17).c_str());
-            mClient.setClientId(clientId);
+            snprintf(mClientId, 24, "%s-%s%s%s", mDevName, WiFi.macAddress().substring(9,11).c_str(), WiFi.macAddress().substring(12,14).c_str(), WiFi.macAddress().substring(15,17).c_str());
+            mClient.setClientId(mClientId);
             mClient.setServer(mCfgMqtt->broker, mCfgMqtt->port);
             mClient.setWill(mLwtTopic, QOS_0, true, mqttStr[MQTT_STR_LWT_NOT_CONN]);
             mClient.onConnect(std::bind(&PubMqtt::onConnect, this, std::placeholders::_1));
@@ -598,6 +597,7 @@ class PubMqtt {
         // last will topic and payload must be available trough lifetime of 'espMqttClient'
         char mLwtTopic[MQTT_TOPIC_LEN+5];
         const char *mDevName, *mVersion;
+        char mClientId[24]; // number of chars is limited to 23 up to v3.1 of MQTT
 };
 
 #endif /*__PUB_MQTT_H__*/