Could my plusnet broadband somehow be responsible for wifi calling not working in our house?

[#1]

As BT have just turned off Signal Assist, I now have zero mobile signal at home so thought I would be able to turn to wifi calling to allow me to make calls from home.

However, after a fruitless day dealing with my mobile provider's technical support, all 3 of our iphones fail to register with wifi calling.

I have gone through all the obvious reset network settings, restart phone, remove sim card and try again, etc.

Unfortunately I am not technical, but could the problem be due to my plusnet broadband settings, maybe my router settings?  And are these something that I can change myself?

I have read odd snippets of conversations (which might be out of date) about UDP 500 and 4500, and SIP ALG, but don't know what any of these are.  Also Apple state "Not all Wi-Fi networks work with Wi-Fi Calling" but don't explain anywhere what this statement means or how to check for wifi network compatibility.

Any advice would be gratefully received

[#2]

You should not have to change anything on the router.

Which iPhones do you have and what IOS level?

Which mobile provider?

[#3]

Vodafone wifi calling works fine on my PN connection.

[#4]

@edandsuet 

And 3 network works fine with mine.

Have you connected your phone to the hub? If not, on an iPhone go to your phone settings/WiFi page, select your Plusnet wireless SSID and enter your hub password.

Next go to settings/Mobile data and make sure that WiFi calling is enabled.

Make sure that both of these pages are set to On.

[#5]

The iphones are all fairly old, but they should all be supported.

2 are iphone 5s's

1 is an iphone 6s

The mobile provider is SMARTY on the Three network.  We were plusnet mobile, but I understand plusnet mobile does not support wifi calling.

[#6]

Yes the phones are all connected to our wifi.  We can browse internet, etc. on them.

wifi calling has been enabled on the phones.  It shows as on in both settings -> phone and settings -> mobile data

wifi is turned on. I didn't think you needed to have mobile data turned on for wifi calling to work, but to be honest I have tried with it both on and off

I have also driven about 1km to a nearby car park and made a call using the new sim card to confirm that the sim is working, and screen correctly displays SMARTY as the network provider and I can make calls.

Back home the screen just shows No Service.

[#7]

Just checked the ios versions.

5s's are on 12.5.5 (can't get ios 13 and higher on 5s)

6s is on 14.8.1

[#8]

From what I can see, yes it should work. Provided you are connected to Wi-Fi.

[#9]

FYI, I have a contract Vodafone android 9, and a contract o2 iPhone 11, and they both do WiFi calling on my Plusnet broadband with no problem.