Have you refreshed MxModelReflection after the upgrade? If not, go to the module and use "Click to refresh" to synchronize entities. This usually fixes issues like empty or undefined attributes when sending emails, because it updates the metadata that EmailTemplate and SecureEmail rely on.

Hi Sidheswari Devkar,

Clean deployment folder

After upgrading modules:

1. Stop the app

2. Delete the directory:

deployment/

3. Run the application again — Mendix will rebuild everything.

---Reconfigure "EmailTemplate.IVK_SendEmail" encryption keys

Go to:

Studio Pro → Project → Settings → Custom Runtime Settings

Add or verify below constants:

EncryptionKey= XYZ... (your 32-char key)

If your key is missing after upgrade → sending email will throw runtime errors.

---

Check for conflicting JAR files

Go to:

project > userlib

Remove duplicate or outdated libraries like:

activation.jar

mail.jar

javax.mail*.jar

old SecureEmail jars

old Encryption module jars

Keep only the newest versions from Marketplace.

---

Rebuild Email Template Module

After update:

1. Open EmailTemplate > Configuration

2. Test SMTP configuration

3. Save

4. Send a test email

---

Why this error occurs

In your log you see:

MicroflowEngine.MicroflowException: Exception while executing runtime operation

This happens because:

The new Mendix 9.24 runtime rejects old encryption jars(So take backup and remove the old jars)

SecureEmail requires updated dependencies

Missing or broken encryption key configuration

---

After upgrading Mendix version, always upgrade these modules together to avoid email failures:

Encryption

Secure Email

Email Template

MxModelReflection

MendixCommons

NanoflowCommons