If the Mail app has too much mail and you want to delete this mail so that there’s more free space on your device, then you can select all the emails you don’t need anymore and move them to the trash.

This feature allows you to delete multiple emails and it’s usually reliable, but sometimes, you can get the error message, “Unable to move Message: The message could not be moved to the mailbox trash.”

The Reason You Can’t Delete Mail

The main reason why you’re unable to move the messages to the trash is that there’s a problem with the connection between your iPhone and your email server. You’ll need to re-establish this connection in order to move unwanted emails to the trash.

1. Move Message to Junk

Rather than moving the message to the junk, the Mail app gives you an option to move the emails to the junk. The Trash is the name of the folder where all of your self-deleted emails go, so essentially they’re archived and not deleted.

The junk is the name of the folder where your mail server directs all emails that it deems to be spam – this doesn’t delete the emails, it just moves them into the spam folder out of your inbox.

1. Swipe right on the email that’s causing the error.

2. Tap on more. This is the first option out of the 3.

3. Select Mark from the pop-up.

4. Tap Move to Junk. This will remove this email or multiple emails you selected into the junk folder with all the rest of your spam folders.

2. Sync email with Accounts

You can force your email to sync with your accounts. If an account is having issues syncing with the Mail app, then this could be causing the issue when you try and archive emails. You’ll need to force the Mail app to sync with all of your email accounts.

1. Open the Mail app.

2. Tap on Mailboxes.

3. Swipe down from the middle of the screen. From here, you should see a spinning circle at the bottom indicating that the Mail app is trying to sync.

4. Wait for the Mailbox to say Updated Just Now.

3. Switch from WIFI to Data

If you haven’t already, you can try switching from WIFI to data. If there’s a bad internet connection within your device, it can cause the Mail app to have an issue and stop you from delete mail from your emails server.

If you’re currently using WIFI, you can switch to data vice versa. This will allow you to get an internet connection to check whether this is the cause of the error within the Mail app.

4. Re-add Email Accounts

If there’s a problem with your iPhone and your emails server, then you’ll need to delete all of the current email accounts within your Mail app and re-add them again. This refreshes the connection between the Mail app and your email server.

1. Go to Settings.

2. Tap on Passwords & Accounts > Accounts.

3. Select the Account.

4. Tap Delete Account. This will delete the email from the Mail app and stop the connection between the email server.

5. Go back to Accounts & Password.

6. Tap Add Account.

7. Add the account you recently deleted. Once you’ve done this, you can go back into the Mail and delete some unwanted emails. You should be able to move the message to the Trash from here forward.

5. Delete the Mail App and Restore it

If there’s a software problem within the mail app, you can delete the mail app so the software is wiped from your device, and then restore it again. This will remove any errors within the app and the app should start to function properly once it’s been restored.

1. Hold the Mail app until it starts to jiggle.

2. Tap Delete.

3. Press the Done button to go back to the home screen.

4. Go to the App Store and install Mail.

5. Go back to Settings > Accounts & Passwords > Accounts and re-configure the mail accounts. Once you’re done, you can open the Mail app and move some unwanted emails to the Trash. The message should move to the Trash at this point.

6. Force Restart Device

If there’s a software issue within your iPhone or iPad that affecting the Mail app, then this needs to troubleshoot in order to get the Mail app working again. To fix a software issue, you need to force restart your device. When you force restart your device, the device is turned off, the software is checked and wiped of any errors, and the system is rebooted.

Once your device turned back on again, you can go to the Mail app and try to delete some unwanted emails by moving them to the Trash.

If you have an iPhone 7 or above:

1. Hold the sleep/wake key and the volume down key.

2. Wait for the Apple logo to appear

If you have an iPhone X or 8:

1. Quickly press the release the volume up button.

2. Quickly press the release the volume down button.

3. Press and hold the Power button until you see the Apple logo.

To force restart iPads with home buttons:

1. Hold down the Home button and the power button.

2. Keep both buttons held until the Apple logo appears.

3. Let go of the buttons.

4. Wait for your iPad to restart.

To force restart iPads without a home button:

1. Press and release the Volume Up button.

2. Press and release the Volume Down button.