Error 15 safari

Check this ⤵️

Check -> Change the date and time on iPhone

Change the date and time on iPhone – Apple Support (UK)

If Safari isn't loading websites or quits on your iPhone, iPad, or iPod touch

If Safari isn't loading websites or quits on your iPhone, iPad, or iPod touch - Apple Support

• If you're using a VPN (Virtual Private Network), check your VPN settings. If you have a VPN turned on, some apps or websites might block content from loading.

Force quit Safari, see -> Close an app on your iPhone or iPod touch

Close an app on your iPhone or iPod touch - Apple Support

Clear the history and cookies from Safari on your iPhone, iPad, or iPod touch

Clear the history and cookies from Safari on your iPhone, iPad, or iPod touch - Apple Support

Have you tried accessing the same site on another browser and/or another device? This will isolate if it is only Safari on your device that is behaving like that.

There are numerous reasons that can cause this error, but the primary one is you have filtering on your network that detected the URL as malicious, hence it is blocked.

Are you using any third-party DNS (NextDNS.io, ControlD.com, etc.) or have PiHole on the network OR do you have Safari plug-in/extension that has this functionality? If so, just add the URL to the ALLOW LIST.

OR

Try using a VPN to by-pass your local network filtering. ProtonVPN has a free tier that should be sufficient and is far better than a lot of other free VPNs.