diff --git a/.env.example b/.env.example
index 9e97a2c..e823dea 100644
--- a/.env.example
+++ b/.env.example
@@ -19,4 +19,8 @@ SMTP_USER=your-smtp-user@example.com
 SMTP_PASS=your-smtp-password
 
 # The recipient for booking messages (defaults to christian@warme.dk)
-BOOKING_EMAIL=christian@warme.dk
\ No newline at end of file
+BOOKING_EMAIL=christian@warme.dk
+SENDER_EMAIL=christian@warme.dk
+
+# Notes: If your account uses MFA, create an app password for SMTP and use it in SMTP_PASS.
+# Office365 settings: SMTP_HOST=smtp.office365.com, SMTP_PORT=587 (STARTTLS)
\ No newline at end of file
diff --git a/README.md b/README.md
index a4259bc..f6d18c2 100644
--- a/README.md
+++ b/README.md
@@ -80,3 +80,25 @@ Notes:
 - Generated images can be large; a small number of generated images were removed from git and the project ignores `public/img/generated/`. If you want generated images checked into the repo, move them into `public/img/` and commit explicitly.
 - For production process management the project includes PM2 scripts in `package.json` (see `pm2:*` scripts).
 
+### Office365 / SMTP (app password)
+
+If you plan to use an Office365 mailbox with SMTP (app password):
+
+1. Enable SMTP AUTH for the mailbox (tenant settings may block it by default).
+2. If the mailbox has MFA enabled, create an app password for the mailbox and use it as `SMTP_PASS`.
+   - Microsoft 365: My account -> Security info -> Add method -> App password (or use admin center to manage).
+3. Set these env vars in your local `.env`:
+
+```bash
+SMTP_HOST=smtp.office365.com
+SMTP_PORT=587
+SMTP_USER=christian@warme.dk
+SMTP_PASS=your-app-password
+SENDER_EMAIL=christian@warme.dk
+BOOKING_EMAIL=christian@warme.dk
+```
+
+4. The contact API will send mail using the authenticated mailbox as the From address and set Reply-To to the visitor's email so replies go to them.
+
+If you prefer a more modern and robust approach we can switch to Microsoft Graph API with OAuth2 (recommended for production).
+
diff --git a/src/app/api/contact/route.ts b/src/app/api/contact/route.ts
index 2067be0..d1b07e9 100644
--- a/src/app/api/contact/route.ts
+++ b/src/app/api/contact/route.ts
@@ -49,11 +49,18 @@ export async function POST(req: Request) {
       <div>${message.replace(/\n/g, '<br/>')}</div>
     `
 
+    // For Office365 SMTP with an app-password, the 'from' address usually
+    // must be the authenticated mailbox. Use SENDER_EMAIL (or SMTP_USER)
+    // as the From, and set Reply-To to the form submitter so replies go to them.
+    const senderEmail = process.env.SENDER_EMAIL || user
+
     await transporter.sendMail({
-      from: `${name} <${email}>`,
+      from: senderEmail,
+      replyTo: `${name} <${email}>`,
       to,
       subject,
-      html
+      html,
+      text: `${name} (${email})\n\n${message}`
     })
 
     return NextResponse.json({ ok: true })