diff --git a/src/languageservice/services/yamlCompletion.ts b/src/languageservice/services/yamlCompletion.ts
index be21a8bb..513a23d6 100644
--- a/src/languageservice/services/yamlCompletion.ts
+++ b/src/languageservice/services/yamlCompletion.ts
@@ -293,7 +293,7 @@ export class YamlCompletion {
       proposed,
     };
 
-    if (this.customTags.length > 0) {
+    if (this.customTags && this.customTags.length > 0) {
       this.getCustomTagValueCompletions(collector);
     }
 
diff --git a/test/autoCompletion.test.ts b/test/autoCompletion.test.ts
index dd5abe0c..eba8fa6d 100644
--- a/test/autoCompletion.test.ts
+++ b/test/autoCompletion.test.ts
@@ -3126,5 +3126,10 @@ describe('Auto Completion Tests', () => {
         expect(result.items.map((i) => i.label)).to.have.members(['fruit', 'vegetable']);
       });
     });
+    it('Should function when settings are undefined', async () => {
+      languageService.configure({ completion: true });
+      const content = '';
+      await parseSetup(content, 0);
+    });
   });
 });