diff --git a/src/transporter.ts b/src/transporter.ts
index 7c27269..388b5c7 100644
--- a/src/transporter.ts
+++ b/src/transporter.ts
@@ -1,10 +1,11 @@
 // @deno-types="npm:@types/nodemailer"
 import nodemailer from 'nodemailer'
 
-const dkimPrivateKey = await Deno.readTextFile(
-	'/home/julien/dkim_sendmail_keys/dkim_sendmail_cohabit_fr.pem',
-).catch((cause) => {
-	throw new Error('unable to load DKIM private key', { cause })
+const dkimPath = '/home/julien/dkim_sendmail_keys/dkim_sendmail_cohabit_fr.pem'
+const dkimPrivateKey = await Deno.readTextFile(dkimPath).catch((cause) => {
+	throw new Error(`unable to load DKIM private key from "${dkimPath}"`, {
+		cause,
+	})
 })
 
 export const transporter = nodemailer.createTransport({