How to Fix Delayed iMessages After Moving to iPhone 18

For delayed iMessages, first check whether the delay affects every conversation or only one contact, and whether messages arrive over Wi-Fi, cellular data, or both. An iPhone 18 or iOS 27 mention is context, not proof of the cause.

Start with the connection

Check that Wi-Fi or cellular data is working in another app, then restart the iPhone.
Install an available iOS update through Settings > General > Software Update.
Try another network and ask a contact to send a new message rather than relying on an old delayed thread.
If you reset network settings, note that Apple says this also removes saved Wi-Fi networks and passwords, cellular settings, and used VPN and APN settings.

When to involve the carrier or Apple

If SMS messages as well as iMessages are late, ask the carrier to check the line. If the issue is limited to iMessage after the basic checks, contact Apple Support with the affected number, timing, and network type. Do not treat a network reset as a guaranteed fix.

If Apple's built-in steps do not resolve a broader software problem, Dr.Fone - System Repair provides a guided desktop workflow for iOS system issues before you consider a full erase.