diff --git a/packages/@aws-cdk/aws-gamelift-alpha/lib/build.ts b/packages/@aws-cdk/aws-gamelift-alpha/lib/build.ts
index cda284374ce6e..6bf94f1831b07 100644
--- a/packages/@aws-cdk/aws-gamelift-alpha/lib/build.ts
+++ b/packages/@aws-cdk/aws-gamelift-alpha/lib/build.ts
@@ -314,12 +314,12 @@ export class Build extends BuildBase {
   }
 
   private validateServerSdkVersion(serverSdkVersion?: string) {
-    if (!serverSdkVersion) return;
+    if (serverSdkVersion === undefined || cdk.Token.isUnresolved(serverSdkVersion)) return;
     if (!serverSdkVersion.match(/^\d+\.\d+\.\d+$/)) {
-      throw new Error(`serverSdkVersion must be in the 0.0.0 format, got ${serverSdkVersion}.`);
+      throw new Error(`serverSdkVersion must be in the 0.0.0 format, got \'${serverSdkVersion}\'.`);
     }
     if (serverSdkVersion.length > 128) {
-      throw new Error(`serverSdkVersion length must be smaller than or equal to 128, got ${serverSdkVersion}.`);
+      throw new Error(`serverSdkVersion length must be smaller than or equal to 128, got ${serverSdkVersion.length}.`);
     }
   }
 }
diff --git a/packages/@aws-cdk/aws-gamelift-alpha/test/build.test.ts b/packages/@aws-cdk/aws-gamelift-alpha/test/build.test.ts
index 6b077ca225be3..b2d1698f273f5 100644
--- a/packages/@aws-cdk/aws-gamelift-alpha/test/build.test.ts
+++ b/packages/@aws-cdk/aws-gamelift-alpha/test/build.test.ts
@@ -190,14 +190,14 @@ describe('build', () => {
         expect(() => new gamelift.Build(stack, 'BuildWithInvalidServerSdkVersion', {
           content,
           serverSdkVersion: 'invalid',
-        })).toThrow(/serverSdkVersion must be in the 0.0.0 format, got invalid./);
+        })).toThrow(/serverSdkVersion must be in the 0.0.0 format, got 'invalid'./);
       });
 
       test('with an incorrect serverSdkVersion length', () => {
         expect(() => new gamelift.Build(stack, 'BuildWithInvalidServerSdkVersion', {
           content,
           serverSdkVersion: '1'.repeat(50) + '.' + '1'.repeat(50) + '.' + '1'.repeat(50),
-        })).toThrow(/serverSdkVersion length must be smaller than or equal to 128/);
+        })).toThrow(/serverSdkVersion length must be smaller than or equal to 128, got 152./);
       });
     });
   });