diff --git a/dist/bar.js b/dist/bar.js
index ec25ca6..c22e59c 100644
--- a/dist/bar.js
+++ b/dist/bar.js
@@ -17,43 +17,46 @@ export const bar = {
                 </ha-card>
             `;
             this.content = this.querySelector("div.card-content");
-
-            this.config.sensors.forEach((sensor) => {
-                let humidity = this._hass.states[sensor.humidity].state;
-                let temperature = this._hass.states[sensor.temperature].state;
-                let leafTemperature = temperature - (this.config.leaf_temperature_offset || 2);
-                if (sensor.leaf_temperature !== undefined) {
-                    leafTemperature = this._hass.states[sensor.leaf_temperature].state;
-                }
-                let vpd;
-                if (sensor.vpd !== undefined) {
-                    vpd = this._hass.states[sensor.vpd].state;
-                } else {
-                    vpd = this.calculateVPD(this.toFixedNumber(leafTemperature), this.toFixedNumber(temperature), this.toFixedNumber(humidity)).toFixed(2);
-                }
-
-                let card = this.content.querySelector(`ha-card[data-sensor="${sensor.name}"]`);
-                if (!card) {
-                    card = document.createElement('ha-card');
-                    card.dataset.sensor = sensor.name;
-                    card.className = 'vpd-card';
-                }
-                // if sensor.name is not empty than show in the card
-                let html = `<div class="bar">`;
-                if (sensor.name !== "") {
-                    html += `<span class="vpd-title">${sensor.name}</span>`;
-                }
-                html += `<span class="vpd-value">${vpd} ${this.kpa_text || ''}</span>`;
-                html += `<span class="vpd-rh">${humidity}%</span>`;
-                html += `<span class="vpd-temp">${temperature} ${this.unit_temperature}</span>`;
-                html += `<span style="background: ${this.getColorForVpd(vpd)}" class="vpd-state ${this.getPhaseClass(vpd)}"><span>${this.getPhaseClass(vpd)}</span></span>`;
-                html += `<span class="vpd-history" style="float:right;"><canvas></canvas></span>`;
-                html += `</div>`;
-                card.innerHTML = html;
-                this.content.appendChild(card);
-            });
+            if (this._hass) {
+                this.config.sensors.forEach((sensor) => {
+                    let humidity = this._hass.states[sensor.humidity].state;
+                    let temperature = this._hass.states[sensor.temperature].state;
+                    let leafTemperature = temperature - (this.config.leaf_temperature_offset || 2);
+                    if (sensor.leaf_temperature !== undefined) {
+                        if (this._hass.states[sensor.leaf_temperature] !== undefined) {
+                            leafTemperature = this._hass.states[sensor.leaf_temperature].state;
+                        }
+                    }
+                    let vpd;
+                    if (sensor.vpd !== undefined) {
+                        vpd = this._hass.states[sensor.vpd].state;
+                    } else {
+                        vpd = this.calculateVPD(this.toFixedNumber(leafTemperature), this.toFixedNumber(temperature), this.toFixedNumber(humidity)).toFixed(2);
+                    }
+
+                    let card = this.content.querySelector(`ha-card[data-sensor="${sensor.name}"]`);
+                    if (!card) {
+                        card = document.createElement('ha-card');
+                        card.dataset.sensor = sensor.name;
+                        card.className = 'vpd-card';
+                    }
+                    // if sensor.name is not empty than show in the card
+                    let html = `<div class="bar">`;
+                    if (sensor.name !== "") {
+                        html += `<span class="vpd-title">${sensor.name}</span>`;
+                    }
+                    html += `<span class="vpd-value">${vpd} ${this.kpa_text || ''}</span>`;
+                    html += `<span class="vpd-rh">${humidity}%</span>`;
+                    html += `<span class="vpd-temp">${temperature} ${this.unit_temperature}</span>`;
+                    html += `<span style="background: ${this.getColorForVpd(vpd)}" class="vpd-state ${this.getPhaseClass(vpd)}"><span>${this.getPhaseClass(vpd)}</span></span>`;
+                    html += `<span class="vpd-history" style="float:right;"><canvas></canvas></span>`;
+                    html += `</div>`;
+                    card.innerHTML = html;
+                    this.content.appendChild(card);
+                });
+            }
         }
-
+        console.log()
         this.updateBars();
         this.updateVPDLegend();
 
diff --git a/dist/ha-vpd-chart-editor.js b/dist/ha-vpd-chart-editor.js
index 9a0ef56..c62fc44 100644
--- a/dist/ha-vpd-chart-editor.js
+++ b/dist/ha-vpd-chart-editor.js
@@ -165,7 +165,11 @@ export class HaVpdChartEditor extends HTMLElement {
         const index = target.getAttribute('data-index');
         let value = target.value;
         if (this._vpd_phases[index].className !== value) {
-            this._config.vpd_phases[index].className = value;
+            if (Object.isExtensible(this._config.vpd_phases[index])) {
+                this._config.vpd_phases[index].className = value;
+            } else {
+                console.warn('Cannot define property on a non-extensible object');
+            }
             fireEvent(this, 'config-changed', {config: this._config});
         }
     }
@@ -356,7 +360,13 @@ export class HaVpdChartEditor extends HTMLElement {
 
         configValues.forEach(({id, prop, type}) => {
             const element = this.shadowRoot.querySelector(`#${id}`);
-            if (element) element[type] = this[prop];
+            if (element) {
+                if (Object.isExtensible(element)) {
+                    element[type] = this[prop];
+                } else {
+                    console.warn('Cannot define property on a non-extensible object');
+                }
+            }
         });
 
         const minVPD = this.toFixedNumber(this.calculateVPD(this._max_temperature - this._leaf_temperature_offset, this._max_temperature, this._max_humidity));
diff --git a/dist/ha-vpd-chart.js b/dist/ha-vpd-chart.js
index d8b42f9..3de62e9 100644
--- a/dist/ha-vpd-chart.js
+++ b/dist/ha-vpd-chart.js
@@ -1,5 +1,5 @@
 // Set version for the card
-window.vpdChartVersion = "1.3.8";
+window.vpdChartVersion = "1.3.9";
 
 import {methods} from './methods.js';
 import {chart} from './chart.js';