diff --git a/src/datasource-zabbix/utils.ts b/src/datasource-zabbix/utils.ts
index c5ba1e9..03f1c29 100644
--- a/src/datasource-zabbix/utils.ts
+++ b/src/datasource-zabbix/utils.ts
@@ -302,6 +302,9 @@ export function callOnce(func, promiseKeeper) {
         .then(result => {
           promiseKeeper = null;
           return result;
+        }).catch(err => {
+          promiseKeeper = null;
+          throw err;
         })
       );
     }
diff --git a/src/datasource-zabbix/zabbix/proxy/cachingProxy.ts b/src/datasource-zabbix/zabbix/proxy/cachingProxy.ts
index 5d11628..1fa78e2 100644
--- a/src/datasource-zabbix/zabbix/proxy/cachingProxy.ts
+++ b/src/datasource-zabbix/zabbix/proxy/cachingProxy.ts
@@ -65,6 +65,9 @@ function callOnce(func, promiseKeeper, funcScope) {
         .then(result => {
           promiseKeeper[hash] = null;
           return result;
+        }).catch(err => {
+          promiseKeeper[hash] = null;
+          throw err;
         })
       );
     }