Remove missing Content-Type.

worker/sender.go

@@ -34,7 +34,7 @@ func appendSignature(request *http.Request, body *[]byte, KeyID string, publicKe
 
 func sendActivity(inboxURL string, KeyID string, body []byte, publicKey *rsa.PrivateKey) error {
 	req, _ := http.NewRequest("POST", inboxURL, bytes.NewBuffer(body))
-	req.Header.Set("Content-Type", "application/activity+json, application/ld+json")
+	req.Header.Set("Content-Type", "application/activity+json")
 	req.Header.Set("User-Agent", uaString)
 	req.Header.Set("Date", httpdate.Time2Str(time.Now()))
 	appendSignature(req, &body, KeyID, publicKey)