diff --git a/docs/deprecations.md b/docs/deprecations.md
index 9c3d8714a..4bdfc1b19 100644
--- a/docs/deprecations.md
+++ b/docs/deprecations.md
@@ -382,6 +382,8 @@ Please use `provider.kmsKeyArn` and `functions[].kmsKeyArn`. `service.awsKmsKeyA
 
 Deprecation code: `RESOURCES_EXTENSIONS_REFERENCE_TO_NONEXISTENT_RESOURCE`
 
+_Note: This deprecation was replaced with a thrown error (adding a deprecation here, was a logical error). Please upgrade to latest version of the Framework_
+
 Starting with v3.0.0, extensions to nonexistent resources in `resources.extensions` will throw an error instead of passing silently.
 
 <a name="DISABLE_LOCAL_INSTALLATION_FALLBACK_SETTING"><div>&nbsp;</div></a>
diff --git a/lib/plugins/aws/package/lib/mergeCustomProviderResources.js b/lib/plugins/aws/package/lib/mergeCustomProviderResources.js
index 85a99005a..314d5aa41 100644
--- a/lib/plugins/aws/package/lib/mergeCustomProviderResources.js
+++ b/lib/plugins/aws/package/lib/mergeCustomProviderResources.js
@@ -30,10 +30,9 @@ module.exports = {
       for (const [resourceName, resourceDefinition] of Object.entries(extensions)) {
         for (const [extensionAttributeName, value] of Object.entries(resourceDefinition)) {
           if (!template.Resources[resourceName]) {
-            template.Resources[resourceName] = {};
-            this.serverless._logDeprecation(
-              'RESOURCES_EXTENSIONS_REFERENCE_TO_NONEXISTENT_RESOURCE',
-              'Starting with next major version, extensions to nonexistent resources will throw an error instead of passing silently.'
+            throw new ServerlessError(
+              `Cannot extend "${resourceName}" resource, as it's not found in generated stack`,
+              'RESOURCE_EXTENSION_NOT_EXISTING'
             );
           }