SSL certificate error on iPhone XR after iOS 18 update

An SSL certificate error is not generated by the iPhone or iOS itself. Such errors generally originate from the website or email server that the device is attempting to connect to. They may occur for several reasons, such as an expired certificate, an incorrectly configured server, a certificate issued by an untrusted Certificate Authority (CA), or a mismatch between the certificate and the server's domain name.

If you encounter an SSL certificate error while accessing an email account or a website, the first step should be to investigate the server or email service configuration rather than assuming that there is a problem with the iPhone.

Installing a trust certificate on an iPhone is not a routine troubleshooting step and should not be undertaken without understanding its purpose. Identifying whether a certificate is legitimate, trustworthy, and issued by an appropriate Certificate Authority requires a certain level of technical expertise.

Installing an untrusted or malicious certificate can compromise your privacy and security. Depending on the certificate type and how it is configured, it may allow an attacker to intercept or inspect certain encrypted communications.

Therefore, do not install a certificate simply because a website, email server, or troubleshooting guide prompts you to do so. Verify its authenticity and source first. If the certificate is required for a legitimate corporate, institutional, or email service, obtain it directly from the organization's IT administrator or an authoritative source.

In most cases, the appropriate solution is to correct the server's SSL/TLS certificate configuration, not to install an unfamiliar certificate on the iPhone.

Milena1989 wrote:

...on iPhone XR after iOS 18 Update

Not every issue an individual encounters on their device can be attributed to an iOS update. iOS 27 or later may have coincided with what you are experiencing, but that does not mean the issue was triggered by iOS. Coincidence in timing is not, by itself, evidence of causation.

If the update itself were the root cause, then every device running that same version of iOS would exhibit the identical problem. In such a scenario, the forums would be flooded with countless posts reporting the same malfunction, creating an unmistakable wave of complaints that no one could possibly overlook.

The absence of such widespread reports strongly indicates that the issue is not a general, system-wide problem with iOS 27 or later, but rather something specific to the individual device, its configuration, installed apps, settings, hardware, or another interacting factor.

In short: iOS 27 or later may be a coincidence in timing, but there is no basis to conclude that iOS itself triggered the problem simply because the issue appeared after the update.

See what each update does: About iOS 27 Updates, About iOS 26 Updates, About iOS 18 Updates, About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...