Why is RCS not working between my iPhone running iOS 18 and Android?

Mine had stopped working properly but after I did a network reset on my iPhone it’s been working.

Turn off your Wifi. I was connected to my company's wifi network and my RCS messages to my wifes android phone wasn't working. Walked outside and the wifi disconnected and all the messages went through with no problem.

Total fact. It is the carrier and not Apple. I have just discovered that it can be the line if everything you have done on the phone to fix the problem doesn’t work that it is the line. Once they cab reset the line then RCS will work.

Remember, RCS is a cellular carrier service, not an Apple service. Turning off WiFi means your iPhone is forced to use its carrier signal. Do you have Wi-Fi-Calling enabled on your iPhone? Who is your carrier? Does your carrier even support WiFi Calling? WiFi Calling means your phone will attempt to make phone calls over the WiFi network it’s connected to instead of the cellular carrier you use. You should not have to turn off WiFi altogether to use RCS. This sounds purely like your carrier is at fault here. And as you have noticed in the post just below yours @Fuzzylobes switched from T-mobile to AT&T and RCS is working fine now. Again, this is a Cellular carrier issue, NOT an Apple issue.

Settings->Cellular->Wi-Fi-Calling. If it’s on try turning it off. If it’s off try turning it on. Test

For what’s it’s worth, my carrier is AT&T, I have WiFi calling enabled, and RCS works just fine for me.

In my case, the problem is that RCS messages don't come in when the phone is on my home WiFi network. If I turn off WiFi on the phone, or step outside, out of WiFi range, all the RCS messages that have been held up arrive all at once. (Re-posting this info, in case it helps anyone else.)

Go to your iMessage settings do the following

Turn iMessages off

Turn RCS off

Turn iMessage on, wait for it to connect

Turn RCS on

Should fix your issue of not working, did for all my iPhones

Works fine on my iPhone 15 Pro Max on both the Verizon line and T-Mobile line. You may need to contact Verizon to make sure there isn’t a provision on their end that needs to be enabled or if you have to have specific plans (sometimes older grandfathered plans may be excluded from some features).

I would disable rcs chat on both phones, and then do a setting reset on the iPhone and an app reset on the android phone. on the android phone you may also have to stop the google messaging app and clear cache and data, then start it back up.

apple Reset iPhone settings to their defaults - Apple Support

Droid/ google https://support.google.com/messages/answer/9363493?hl=en#zippy=%2Cstep-clear-google-messages

I would disable rcs chat on both phones, and then do a setting reset on the iPhone and an app reset on the android phone. on the android phone you may also have to stop the google messaging app and clear cache and data, then start it back up.

apple Reset iPhone settings to their defaults - Apple Support

Droid/ google https://support.google.com/messages/answer/9363493?hl=en#zippy=%2Cstep-clear-google-messages

If you go into the settings and reset the network settings under General, it will fix the RCS issue. I had the same issue and that fixed it for me

Crazy enough, I was on T-Mobile and had the same issue, T-Mobile customer service kept giving me the run around about how to fixing RCS not working. Fed up and insulted I switched to AT&T and RCS started to work. The problem can also ultimately be the line on your carrier account can be corrupted and they need to delete it and create a new line and add your number back into that line for it to work. Unfortunately, no customer service rep could figure that out.

T-Mobile keeps putting me off. I get a FB message every few days saying that their engineers haven’t looked at it. So I have been playing with my phone, trying to figure out if there is something to do. Things I’ve tried and I am judging whether it is on based n General > About, tap on Carrier, and see what it list. If RCS is on, it will say Voice, SMS, & RCS. If RCS is off, it says Voice & SMS. None of this has anything to do with recipient.

1. Turn phone off and on. It comes back on but it turns off after 30 minutes.
2. Reset Network Settings. It comes back on but again, only for 30 minutes or so.
3. Switch on and off RCS in Settings > Apps > Messages > RCS Messaging. This does nothing.

I normally keep my phone on LTE because 5G isn’t that great around here and LTE is often more reliable. So I tried turning on 5G and again, it made no difference. I went to the store today and sent a text to my wife telling her that I was on my way back and I noticed that RCS was on. After I got home, I noticed that SMS was back on. I always keep my phone connected to wifi so I turned it off and after a few minutes, RCS turned back on. I have left wifi off this afternoon and it is still connected to RCS three hours later. 🤷

I am going to keep wifi off and see if it fixes it. For reference, I have an ASUS ZenWiFi XT-8 router.

For me after upgrading to an iPhone 16 Pro Max from an iPhone 13 Pro Max and seeing that RCS wasn’t working, it confirmed that it was the carrier. My carrier was T-Mobile and it was an issue with my line that customer service or their so-called tech support didn’t have the knowledge on how to resolve it. So switched to AT&T and now RCS works. Therefore my suggestion is if your carrier will not create a knew line after trying everything else, then port out to a different cellular carrier and then come back to your original carrier at a later date.

Hello everyone, at our company we discovered that apple connects to the fqdn from google for the rcs service via port TCP 443 and TCP 5223. One of this connections to the same fqdn but different port has no dns propagated out in the Internet. If you use a solution where the gateway will do a dns resolution tentative, it will most likely fail because the IP given is not the same initiated by the device and if this happens the connection to the servet from google will fail. We resolved it very simple and excluded the fqdn from being resolved at our gateway (web proxy). This only happens in Apple devices, for android this behavior is not observed. So i think Apple should make this transparent as more and more companies that use this type of solutions will suffer from the same. Also maybe change the way the connection is made so it does not has the depency under an IP given by the system and move to more dynamic and compatible way with other systems or solutions.

Just checking in to say that since I disconnected my phone from wifi at home, I haven’t had RCS drop once. It’s been almost two weeks now. So somehow my router was causing the issue. Unfortunately I don’t know much of anything, so I have no idea how to fix it. I talked to my ISP and they aren’t blocking any ports. So I guess I’m stuck on no wifi which kind of but there really isn’t anything I can do about it. It may just be a quirk of my router.

[Edited by Moderator]