add retry for sending mail *sigh*

helpers/mail.ts

@@ -2,6 +2,7 @@ import { Booking } from '../db/booking'
 import { getBaseURL } from '../helpers/url'
 import { daysFormatFrontend } from './date'
 import { generateCalendarEntry } from './ical'
+import { retryWithDelay } from './retryWithDelay'
 
 const SENDGRID_API_KEY = process.env.SENDGRID_API_KEY
 const ADMIN_EMAIL = process.env.ADMIN_EMAIL
@@ -195,12 +196,17 @@ async function sendMail({
     },
     body: JSON.stringify(data),
   }
-  const resp = await fetch(SENDGRID_URL, fetchOptions)
-  const bodyText = await resp.text()
 
-  if (!resp.ok) {
-    throw new Error(
-      `Unable to send mail, status ${resp.status} ${resp.statusText}, ${bodyText}`
-    )
-  }
+  return retryWithDelay({
+    run: async () => {
+      const resp = await fetch(SENDGRID_URL, fetchOptions)
+      const bodyText = await resp.text()
+
+      if (!resp.ok) {
+        throw new Error(
+          `Failed to send mail with status ${resp.status}: ${bodyText}`
+        )
+      }
+    },
+  })
 }