To stop your iPhone from marking email addresses red, open Settings, tap Apps > Mail, tap Mark Addresses (below Composing), and delete every domain in the list. With the list empty, the Mail app shows all addresses in the normal color again.
These steps are for Apple’s built-in Mail app on iOS 18 and later, including iOS 27, and the same setting is on an iPad. On iOS 17 and earlier, Mail appears directly in Settings with no Apps step. The Gmail and Outlook apps do not use this setting.
Why Email Addresses Turn Red on iPhone
Red addresses come from a Mail feature called Mark Addresses. According to Apple’s Change your Mail settings on iPhone guide, you enter the domains in your organization, and Mail shows the names of people outside those domains in red. A domain is the part of an address after the @ sign, such as gmail.com. The feature is off until someone types a domain into it, so if you see red names, a domain was entered at some point, perhaps during a work setup.
How to Stop iPhone Mail From Marking Addresses Red
- Open the Settings app.
- Tap Apps, then tap Mail. On iOS 17 and earlier, tap Mail directly in Settings.
- Scroll to the Composing section and tap Mark Addresses. A text field shows the domains that will not be marked, such as
apple.com, example.org. - Tap the field and delete everything in it, including any commas or spaces. With nothing left, no addresses are marked in red.
- Tap the back arrow at the top left to return to Mail settings. The change saves on its own.
- Open Mail and start a new message. Recipients you add now appear in the normal color.
Keep the Warning, but Fix Which Addresses Turn Red
If you like the warning but it marks addresses you trust, edit the list instead of clearing it. In Mark Addresses, type each trusted domain separated by commas, for example yourcompany.com, gmail.com, icloud.com. Only addresses that end with a listed domain stay in the normal color.
Enter domains only, not full addresses, and check the spelling. A typo in your own company’s domain turns every coworker red. If you also use a personal address in Mail, add its domain too, or your own name will show in red in the From field. To turn the warning back on later, return to the same screen and type your domains again.
Signature sits in the same Composing section, and it is where you get rid of Sent from my iPad on emails sent from an iPad.
How Mark Addresses Works
- It checks the domain. If the domain of an address is not in your list, the name appears in red.
- It applies to sent and received mail. Apple says names outside your domains appear in red whether you send them an email or receive one from them, so you may also see red in the From field.
- It is only a visual warning. Red addresses are not blocked, and your messages still send normally.
- It does not catch every mistake. A wrong person at an allowed domain stays in the normal color, so still read the To line before you tap Send.
- It is set per device. Your iPhone, iPad and Mac each keep their own list.
Stop Red Addresses in Mail on a Mac
The Mac has a separate setting. In the Mail app on your Mac, choose Mail > Settings, click Composing, and deselect Mark addresses not ending with. It sits with the other Mail for Mac Composing settings. Changing it on one device does not change it on the other.
If You Cannot Find or Change the Setting
- No Apps entry in Settings. You are on iOS 17 or earlier. Tap Mail in the main Settings list instead.
- Mail is missing from the list. Type “Mark Addresses” in the search field at the top of Settings. If Mail is not installed, the red names are coming from another app, so check that app’s settings.
- The names are still red. Close the draft and start a new message. Make sure the field is fully empty, not holding a single space or comma.
- It is a work iPhone. Check Settings > General > VPN & Device Management for a work or school profile. Your organization may want the warning kept on, so ask your IT department before you clear it. For accounts that cannot be edited at all, see why email accounts are grayed out on an iPhone.
Red Email Address Questions
Does a red email address mean the address is wrong?
Not usually. It means the address is outside the domains listed in Mark Addresses. Still, double-check the spelling before you send.
Why is my own address red in the From field?
Your own domain is not in the Mark Addresses list. Add it, or clear the list.
Can other people see the red color?
No. The color only appears in Mail on your device and does not change the message the recipient gets.
Does this also stop red names on my iPad?
Only if you change it there too. The iPad has the same Mark Addresses option under Settings > Apps > Mail.
More iPhone Mail Guides
Matthew Burleigh is the founder, head writer, and editor of Solve Your Tech, which he launched in 2012. He has written technology tutorials since 2008 and worked in IT since 2003, including small-business support, IT management, and consulting. He holds Bachelor’s and Master’s degrees in Computer Science from Arizona State University.
Matthew writes practical guides for Windows, iPhone and iPad, Microsoft Office, Outlook, Google apps, and Android. Solve Your Tech’s guides are checked step by step against the device or app maker’s own documentation and tested on his own devices whenever he has the hardware or software, with clear steps, sources, and update dates.
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