Knowledge Base

Troubleshooting problems with emails and email signatures on mobile devices


You experience various problems with signatures and email layout when you send emails from mobile devices. For example, when you use a mobile device to reply to / forward a message that includes images and formatting, the layout of this message falls apart.


When the user forwards or replies to a message, the mobile device's email client might modify the message thread, by changing the email's format and reply separators or removing some elements. This is usually done for security purposes or to reduce the size of an email. You may experience various signature-related issues, depending on the used mobile device and software. Use the links below to learn about the most common problems and recommended solutions.

Images disappear from emails when replying from iPhone or iPad

When you use an iPhone or iPad to respond to an email, images embedded in the email body disappear from the conversation. This is the default behavior in all recent versions of the iOS operating system.

Luckily, if you use software from the CodeTwo Exchange Rules family, you can bring these pictures back via a dedicated action: Restore images removed by iPhone and iPad. The action is available in CodeTwo Exchange Rules and CodeTwo Exchange Rules Pro.

Email formatting is changed when using Microsoft Outlook for Android

You experience the following issue: emails replied to or forwarded via Microsoft Outlook for Android fall apart if they contain embedded pictures. For example, if an email contains a signature with images (Fig. 1., left side), then after your reply the signature layout and formatting changes (Fig. 1., right side), images get resized, etc.

A signature with images before (left) and after (right) using the Load Full Message option in MS Outlook on an Android device.
Fig. 1. A signature with images before (left) and after (right) using the Load Full Message option in MS Outlook on an Android device.

This problem occurs when you reply to / forward an email in Outlook for Android and select the Load Full Message option (Fig. 2.). When the email is loaded into the body of your new message, the email's format is changed, which breaks the structure of the signature with images. This behavior is not related to CodeTwo software.

The Load Full Message option in Outlook for Android might change email formatting.
Fig. 2. The Load Full Message option in Outlook for Android might change email formatting.

To solve this issue, do not load your messages when replying or forwarding in MS Outlook on your Android device.


This issue was reported in devices running Android 5.0 and later, but earlier versions might also be affected.

Cloud (server-side) signatures not displayed in the Apple Mail app on iOS

A cloud signature added by CodeTwo software is not displayed when you open emails in Apple Mail on iOS. The signature is displayed correctly in other email apps on the same device, e.g. Outlook for iOS, so the problem is not related to the signature itself.

To tackle the problem, try the solutions presented below:

Reset syncing for the affected email account

First, try to disable and re-enable syncing for the affected email account in the following way:

  1. Open the Settings app and select Mail > Accounts (or Passwords & Accounts in the older iOS versions like iOS 13).
  2. Tap the affected email account (under Accounts).
  3. Turn off email syncing by tapping the toggle switch next to Mail (Fig. 3.).

Disabling email syncing for a sample Outlook email account in Apple Mail.
Fig. 3. Disabling email syncing for a sample Outlook email account in Apple Mail.

  1. Now, force-close the Settings app and wait for about 30 seconds.


    To force-close an app:

    1. Swipe up the screen from bottom to center (iPhone X or later) or double press the Home button (older models).
    2. Swipe right or left to find the app you want to force-close, e.g. the Settings app.
    3. Swipe up on the app's preview to close it.
  2. Next, turn on email syncing back by following the steps 1-3 above and setting the toggle switch to Enabled.
  3. Launch the Apple Mail app, choose the affected account, and swipe down the screen to re-sync the emails.

Disable the Protect Mail Activity feature

You can also try disabling the Protect Mail Activity feature. To do so, open the Settings app, go to Mail > Privacy Protection, and disable the feature using the toggle switch, as shown in Fig. 4.

Disabling the Protect Mail Activity feature in Apple Mail.
Fig. 4. Disabling the Protect Mail Activity feature in Apple Mail.

Signature not displayed in an email thread in the native Mail app on iOS

You take part in an email conversation using the Mail app on your iPhone or iPad. Upon reviewing the thread in the app, you notice that your signature is missing from your responses. Yet, if you view the same thread on any other device and in any other email client, you find out that the signature is actually added by CodeTwo software in a correct way (see Fig. 5.).

Signature missing in the Mail app (left) and displayed correctly in another email client (right) in the same email thread with 3 messages.
Fig. 5. Signature missing in the Mail app (left) and displayed correctly in another email client (right) in the same email thread with 3 messages.

The issue described above may happen due to flawed implementation of message threading in the Apple’s native email client in iOS. The Mail app seemingly presents your messages in a thread as the ones that have been processed by an email server. However, these are actually local copies of messages from the Sent (items) folder. In other words, these messages haven’t been processed by CodeTwo services and hence stamped with a signature. That’s why you are not able to see your signature.

To make matters worse, the Mail app has problems with downloading updated sent items from an email server, which may result in missing signatures as well, even though you’ve enabled the CodeTwo Sent Items Update (SIU) service.

The problem of missing signatures may be also related to the fact that your signature does not have its plain text version set up in the signature template editor. For more information, refer to this section.

Signatures are added to all emails except those sent from mobile devices

If signatures are not added emails sent from mobile devices but are added to all other emails, this might be caused by the lack of the Plain Text layout of your signatures.

Most mobile devices (such as those based on Android, Windows Phone, or iOS) send emails in Plain Text. That is why you need to ensure that a Plain Text signature layout is defined for each signature rule in the CodeTwo software that you use. Learn more about the signature formats and layouts available in:


If you already have an HTML signature created for your rule, you can use the Convert to plain text option (Fig. 6.) available in the template editor of CodeTwo Exchange Rules (in CodeTwo Email Signatures 365, you can access this option via the HTML to plain text button). Your signature will be automatically converted to plain text. You can save the changes and close the editor.

The option to convert an HTML signature to plain text.
Fig. 6. The option to convert an HTML signature to plain text.

Once you have both HTML and Plain Text signature layouts defined for your rules, CodeTwo software adds an appropriate signature version to emails, depending on the device used to send them. In the case of mobile devices, plain text signatures are added. If you prefer to add HTML signatures (which look better as the HTML format offers more customization options), some CodeTwo products allow you to convert plain text emails to HTML. Read our Knowledge Base article to learn about the available options.

Messages from Apple devices and mobile devices are sent in plain text

If emails sent by Apple devices (iPhones, iPads, Macs, etc.) and mobile devices are sent in plain text and you prefer to convert them to HTML (so that HTML signatures are added), you can force email format conversion. See this article for more information.

Images in email signatures load very slowly on mobile Outlook versions

You can learn more about this problem in our Knowledge Base article.

Phone links in email signatures are not recognized by mobile devices

If your signatures contain click-to-call links with phone numbers, and these links do not work on mobile devices, check out this article.

Mobile signatures get mixed with signatures added by CodeTwo software

If mobile signatures (such as Sent from my mobile device) get mixed with signatures added by CodeTwo software, and you get double signatures, you might want to remove the ones from mobile devices. See this article for guidelines.

See also:

Common image-related problems in email signatures

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