diff --git a/packages/frontend/src/components/MkCaptcha.vue b/packages/frontend/src/components/MkCaptcha.vue
index ac42f30fcd..c64bb47e77 100644
--- a/packages/frontend/src/components/MkCaptcha.vue
+++ b/packages/frontend/src/components/MkCaptcha.vue
@@ -123,7 +123,7 @@ function callback(response?: string) {
 function onReceivedMessage(message: MessageEvent) {
 	if (message.data.token) {
 		if (props.instanceUrl && new URL(message.origin).host === new URL(props.instanceUrl).host) {
-			callback(<string>message.data.token);
+			callback(message.data.token);
 		}
 	}
 }