In order to connect to a web server using the certificate associated with the host and domain name of the web server, your device may be tricked into accepting a different digital certificate than the one associated with that web server. This difference in certificates may be caused by an attacker trying to trick you into accepting a different digital certificate for the connection than the one associated with that web server. If you are not sure whether you are connecting to a valid web server, please check for its certificate by visiting its website and verifying its authenticity.
3 Ways to Fix Cannot Verify Server Identity Error
Exit and Restart Mail App
Open the app switcher by double-clicking it.
Swipe to the right to find the Mail app. ..
Swipe up to exit the Mail app.
Update iOS Version
If you are using a Windows 10 device, you can find the Software Update icon in the taskbar. If you are using a Windows 8.1 or Windows 8 device, you can find it in the System Tray.
If you have Automatic Updates enabled on your device, you’ll see available updates as soon as they’re available. To turn off Automatic Updates, just tap on the “not applicable” button.
Reset Network Settings
If you want to transfer your data from your old iPhone to your new iPhone, go to “Settings > General > Transfer or Reset iPhone“. ..
This will reset your network settings to their defaults.
Your passcode will confirm the selection.
Final Words
If you are having trouble connecting to a mail server, your iPhone may be trying to retrieve the server’s SSL certificate and checking its reliability. If the certificate is not from the domain name or it has expired, it is considered unreliable. However, if you are having trouble connecting to a mail server because your device has been reset or upgraded, or because you changed the email server certificate, then this error message may appear.
