diff --git a/lib/extension/availability.js b/lib/extension/availability.js
index dbf486519..f0dd19799 100644
--- a/lib/extension/availability.js
+++ b/lib/extension/availability.js
@@ -95,12 +95,12 @@ class Availability extends Extension {
     }
 
     async handleIntervalNotPingable(device) {
-        const ago = Date.now() - device.lastSeen;
         const resolvedEntity = this.zigbee.resolveEntity(device.ieeeAddr);
         if (!resolvedEntity || !device.lastSeen) {
             return;
         }
 
+        const ago = Date.now() - resolvedEntity.device.lastSeen;
         logger.debug(`Non-pingable device '${resolvedEntity.name}' was last seen '${ago / 1000}' seconds ago.`);
 
         if (ago > Hours25) {