Error: "The new MDM payload does not match the old payload"

When enrolling a device with SimpleMDM, you may receive the following error:

Profile Installation Failed
The new MDM payload does not match the old payload.

If you see this error, it's because the device still has an MDM profile installed on it.
Complete the following steps to remove the old profile:

1. On the iOS device, open "Settings"
2. Tap on "General"
3. Scroll to the bottom of the screen and tap "Profiles & Device Management"
4. Tap "SimpleMDM". Note: You may need to tap a different name if you've previously used a different MDM service.
5. Scroll to the bottom of the screen and tap "Remove Management"
6. Confirm the action

Once these steps have been completed, you will be able to enroll with SimpleMDM successfully.