The most common cause is an expired or mismatched SSL certificate from an email, calendar, or unwanted source, with other causes including redirects caused by malware or unverified configuration profiles.
Common Troubleshooting
As noted above, a mismatch between the domain name and server name often triggers this error. When they don’t match, iPhone flags the certificate as untrusted. Try the following depending on how your email is hosted. Changing the mail server name – If you host email on a VPS, change the mail server name in your settings to match the certificate’s common name (CN). For example, use the exact host shown on the certificate. Fixing the main configuration – If you’re on Shared Hosting, update the incoming/outgoing server fields on your iPhone to use mail.server-name.com instead of mail.website-name.com so they match the certificate. Setting up a free certificate – If you’re using a self‑signed or otherwise invalid certificate on a VPS, install a valid one (for example, from Let’s Encrypt, a trusted CA that provides free SSLs).
1. Use a Secure Network Connection
Public Wi‑Fi can sometimes cause this error. Before trying technical fixes, switch to a trusted network, such as your home Wi‑Fi or your mobile hotspot, and test again. This simple step has resolved the issue for many users.
2. Set the Correct Date and Time On iPhone
Wrong date or time can break certificate checks. Make sure your iPhone matches the current time zone or is set to update automatically.
3. Reboot Your iPhone
Temporary bugs or glitches can trigger this error. Restarting gives your iPhone a fresh start and often clears the issue.
4. Re-add Your Email Account
If the account settings are corrupted, removing and re‑adding the account can help.
5. Reset Network Settings
If the problem persists, your network settings might be the issue. Resetting them often restores a clean connection to the mail server.
6. Disable SSL Encryption
Some users have cleared the error by temporarily turning off SSL for the affected account. This should only be used for testing, and only if your email provider allows non‑SSL connections. If it works, contact your provider to fix the certificate and then turn SSL back on for security.
7. Update iOS Carrier Settings
Outdated carrier settings can affect network and mail connectivity. Update them to make sure everything works smoothly.
8. Download the Latest Software on iPhone
Running an outdated version of iOS can cause errors like this. Updating your iPhone not only fixes bugs but also improves security and stability.
9. Factory Reset
If nothing else works, a factory reset can help. This erases your iPhone and installs a clean copy of iOS. Back up your data first, because this will remove everything. Follow the below guidelines to perform a reset on your iPhone.
