diff --git a/packages/binding-coap/src/coap-server.ts b/packages/binding-coap/src/coap-server.ts
index fab84c86c..5c3025ef3 100644
--- a/packages/binding-coap/src/coap-server.ts
+++ b/packages/binding-coap/src/coap-server.ts
@@ -514,10 +514,11 @@ export default class CoapServer implements ProtocolServer {
             }
         };
 
-        thing
-            .handleObserveProperty(affordanceKey, listener, null)
-            .then(() => res.end())
-            .catch(() => res.end());
+        try {
+            await thing.handleObserveProperty(affordanceKey, listener, null);
+        } finally {
+            res.end();
+        }
 
         res.on("finish", (err: Error) => {
             if (err) {
@@ -674,10 +675,12 @@ export default class CoapServer implements ProtocolServer {
                 }
             };
 
-            thing
-                .handleSubscribeEvent(affordanceKey, listener, interactionOptions)
-                .then(() => res.end())
-                .catch(() => res.end());
+            try {
+                await thing.handleSubscribeEvent(affordanceKey, listener, interactionOptions);
+            } finally {
+                res.end();
+            }
+
             res.on("finish", () => {
                 debug(
                     `CoapServer on port ${this.getPort()} ends '${affordanceKey}' observation from ${Helpers.toUriLiteral(