diff --git a/helpers/mail.js b/helpers/mail.js
index a717404..b2ee7f4 100644
--- a/helpers/mail.js
+++ b/helpers/mail.js
@@ -1,18 +1,33 @@
 const SENDGRID_API_KEY = process.env.SENDGRID_API_KEY
 const SENDGRID_URL = 'https://api.sendgrid.com/v3/mail/send'
+// TODO: move to env
 const BOOKING_ADMIN_EMAIL = 'tomru@mail.id0.link'
-const FROM_EMAIL = 'thomasruoff@gmail.com'
+const FROM_EMAIL = 'pfadibussle@mail.id0.link'
+
+if (!SENDGRID_API_KEY) {
+  throw new Error('NO SENDGRID_API_KEY set!')
+}
+
+if (!SENDGRID_API_KEY) {
+  throw new Error('NO SENDGRID_API_KEY set!')
+}
 
 async function sendMail(data) {
-  const response = await fetch(SENDGRID_URL, {
+  const fetchOptions = {
     method: 'POST',
     headers: {
       'Content-Type': 'application/json',
       Authorization: `Bearer ${SENDGRID_API_KEY}`,
     },
     body: JSON.stringify(data),
-  })
-  return response.json()
+  }
+  const response = await fetch(SENDGRID_URL, fetchOptions)
+
+  if (!repsonse.ok) {
+    throw new Error(
+      `Failed to send booking ${data._id} to booking admin with status ${response.status}: ${response.statusText}`
+    )
+  }
 }
 
 export async function sendReceivedBookingMail(booking) {