iPhone RCS Message Problem on WiFi
I'm currently having an issue where iPhones on our network (iPhone 15 Pro and iPhone 15 Pro Max on iOS 26.4/26.4) are having a problem where after being connected to the Deco BE68 for a period of time (usually at least 4 hours), we stop receiving messages over RCS (iMessage and SMS work fine still). This is only resolved by turning the WiFi off and back on again to reassociate the device with the WiFi network.
This issue begun immediately after upgrading to the Deco BE68 router from our prior WiFi 5 TP-Link unit, and it only happens on our home network (the Deco BE68) so I am fairly certain it is router related. I have tried a handful of troubleshooting items:
1. Turning off fast roaming
2. Assigned a fix IP address reservation to the iPhones
3. Changing DNS settings from the automatic setting to Cloudflare/Google options
4. SIP ALG disabled
5. Private WiFi address and iCloud Relay on the iPhones turned off
6. Tried disabling the WiFi 6E mode on the iPhones (6ghz band off)
7. Forgot the WiFi and re-added (including full network reset from iPhone settings)
Of note, the issue seems to happen at different times for each device and not simultaneously.
We checked that the devices (phone and router) are all up to date. Additionally, I have tried resetting the modem and router and phones. The 2 iPhones are the only device I'm aware of that are impacted by this issue.
We are on wireless backhaul too if that makes a difference (ethernet is not wired in our home currently).
Please advise on next troubleshooting steps for this issue. Thanks!
