Singtel Wifi calling

[vade]

Hi, is anyone else here using Singtel mobile and using Singtel Wifi calling? Is it still working for you?

My situation is this. The Singtel mobile reception at my place is really bad, most of the time only 1 bar or sometimes can't even get any signal. So all along I have been using Singtel Wifi calling to get around this problem. However, recently (I don't know exactly when) Singtel Wifi calling seems to have stopped working. Even when Wifi calling is turned on, it still shows the network as only Singtel instead of Singtel Wifi Calling.

I ran these simple tests:

• I have 4 Singtel mobile lines at home (3 on 5G plan, 1 on 4G plan). All 4 lines are using iPhone, same iOS version. But the 3 5G lines cannot get Wifi calling, while the 4G line can.
• I brought all 4 lines to another place, using another Wifi network to test, same result.
• Then I used my friend's Starhub 5G line at my place with my Wifi, Wifi calling works on his phone.

So I'm pretty sure the problem isn't with my Wifi or home broadband, and my conclusion is I think the problem is with Singtel. I've called Singtel to get them to look into this, still waiting for their response.

 

[A7997A]

Hi, is anyone else here using Singtel mobile and using Singtel Wifi calling? Is it still working for you?

My situation is this. The Singtel mobile reception at my place is really bad, most of the time only 1 bar or sometimes can't even get any signal. So all along I have been using Singtel Wifi calling to get around this problem. However, recently (I don't know exactly when) Singtel Wifi calling seems to have stopped working. Even when Wifi calling is turned on, it still shows the network as only Singtel instead of Singtel Wifi Calling.

I ran these simple tests:

• I have 4 Singtel mobile lines at home (3 on 5G plan, 1 on 4G plan). All 4 lines are using iPhone, same iOS version. But the 3 5G lines cannot get Wifi calling, while the 4G line can.
• I brought all 4 lines to another place, using another Wifi network to test, same result.
• Then I used my friend's Starhub 5G line at my place with my Wifi, Wifi calling works on his phone.

So I'm pretty sure the problem isn't with my Wifi or home broadband, and my conclusion is I think the problem is with Singtel. I've called Singtel to get them to look into this, still waiting for their response.

In Wifi calling, the phone makes a VPN to the provider's gateway.
In case of Singtel & its MVNO, it is epdg.epc.mnc001.mcc525.pub.3gppnetwork.org
5G/4G or ios/Android should not matter as far as your wifi is concern (the gateway side can choose to reject)
So unless you have a firewall blocking the 5G phones, it should not be a problem on your side.

Starhub (& MVNO) uses a different gateway : epdg.epc.mnc005.mcc525.pub.3gppnetwork.org
Simba gateway : epdg.epc.mnc010.mcc525.pub.3gppnetwork.org
M1 (& Maxx) uses a non standard gateway : epdg.mobileone.net.sg

 

[vade]

In Wifi calling, the phone makes a VPN to the provider's gateway.
In case of Singtel & its MVNO, it is epdg.epc.mnc001.mcc525.pub.3gppnetwork.org
5G/4G or ios/Android should not matter as far as your wifi is concern (the gateway side can choose to reject)
So unless you have a firewall blocking the 5G phones, it should not be a problem on your side.

Starhub (and its MVNO) uses a different gateway : epdg.epc.mnc005.mcc525.pub.3gppnetwork.org

This is useful info, thanks.

I am quite sure there isn't any firewall on my phone or on my home network blocking access to the gateway. As mentioned, Wifi calling was working previously on these 3 phones and only recently stopped working. And Wifi calling is working on the phone with the 4G line so there shouldn't be any firewall on my home network blocking this.

I also forgot to mention that I randomly asked a few friends using Singtel mobile to test by turning on Wifi calling on their phone with their home Wifi, and none of them could get Wifi calling working.

 

[AaronFjw]

Seems like im not the only one here... hopefully they can fix this

 

[loganrunning]

FWIW, a single data point.

before i ported out from singtel postpaid, it worked when wifi was enabled, whether home or overseas. Nothing Phone 2

 

[A7997A]

FWIW, a single data point.

before i ported out from singtel postpaid, it worked when wifi was enabled, whether home or overseas. Nothing Phone 2

If you don't mind may we know when did you ported out ?

 

[vade]

@AaronFjw do you recall when it stopped working for you?

Singtel got back to me today and I'll quote them:

I have done a check with our network team, and was informed that there is currently an issue with 5G on Wifi Calling.

If you can toggle down to 4G in the meantime, it should work.

I tried toggling down to 4G, and it still doesn't work. So they said they'll look into it again.

 

[A7997A]

This is useful info, thanks.

I am quite sure there isn't any firewall on my phone or on my home network blocking access to the gateway. As mentioned, Wifi calling was working previously on these 3 phones and only recently stopped working. And Wifi calling is working on the phone with the 4G line so there shouldn't be any firewall on my home network blocking this.

I also forgot to mention that I randomly asked a few friends using Singtel mobile to test by turning on Wifi calling on their phone with their home Wifi, and none of them could get Wifi calling working.

Do you have a more exact time frame in which wifi calling stop working ?

 

[A7997A]

@AaronFjw do you recall when it stopped working for you?

Singtel got back to me today and I'll quote them:

I have done a check with our network team, and was informed that there is currently an issue with 5G on Wifi Calling.

If you can toggle down to 4G in the meantime, it should work.

I tried toggling down to 4G, and it still doesn't work. So they said they'll look into it again.

When using wifi calling, it is not uncommon to turn on airplane mode.
In that scenario, there is no active 5G/4G connection, although your cell services is probably tagged as such, and that can make a difference.

 

[vade]

Do you have a more exact time frame in which wifi calling stop working ?

I only moved into my current place last November, and at that time Wifi calling was definitely working. I can't say for sure when exactly it stopped working, but I only realised the problem in the last couple of weeks when I stopped getting the OTP SMSes for some of the websites I used which I needed.

 

[vade]

When using wifi calling, it is not uncommon to turn on airplane mode.
In that scenario, there is no active 5G/4G connection, although your cell services is probably tagged as such, and that can make a difference.

Sorry, not very clear what you mean. Yes, I'm aware that when there is no active 4G/5G connection (or when airplane mode is on), that's when Wifi calling comes into play.

How does that explain why Wifi calling is working on a 4G line but not on a 5G line now?

 

[kitkat2]

haven’t seen wifi calling popping out on my postpaid lines for like a month. think you are not alone.

 

[A7997A]

Sorry, not very clear what you mean. Yes, I'm aware that when there is no active 4G/5G connection (or when airplane mode is on), that's when Wifi calling comes into play.

How does that explain why Wifi calling is working on a 4G line but not on a 5G line now?

When you are on wifi calling, your iphone can't have active 4G/5G services, so changing 5G/4G setting is irrelevant, as the connection made is the same either way.
(IIRC iphone will only try to switch to wifi calling when there is no active 4G/5G service, unlike Android where there is a choice).

On the provider side (Singtel Gateway), however, will check your VPN connection attempt and decide if they will allow the connection. I am not sure what information is exchanged, but my guess will be the sim card IMSI and using that it looks up some sort of table, and makes a decision based on that.

If Singtel's table for any reason permits only those entries with only 4G subscription, the result will match exactly with your observation. Now we don't know if this is indeed the case, but this scenario matches your description.

Another possibly is the gateway forwards those connection to different backend system depending on whether it is a 4G or 5G subscription, and the one handling the 5G subscription is having some issue (or limitation).

Changing your phone's 5G/4G connection setting will not make a difference in these cases since it is based on subscription.

 

[AaronFjw]

@AaronFjw do you recall when it stopped working for you?

Singtel got back to me today and I'll quote them:

I have done a check with our network team, and was informed that there is currently an issue with 5G on Wifi Calling.

If you can toggle down to 4G in the meantime, it should work.

I tried toggling down to 4G, and it still doesn't work. So they said they'll look into it again.

Think it started happening to me at the start of this month.

Thought it was because my house fibre change out from ST to myrepublic but I also tried another phone on starhub like you and it works.

Tried the 4G solution you provided but seems like not helping also...

 

[froztheart]

Interesting, I shall check it out when back in SG.
Currently no WIFI-Calling when I checked for my ST line.

 

[vade]

When you are on wifi calling, your iphone can't have active 4G/5G services, so changing 5G/4G setting is irrelevant, as the connection made is the same either way.
(IIRC iphone will only try to switch to wifi calling when there is no active 4G/5G service, unlike Android where there is a choice).

On the provider side (Singtel Gateway), however, will check your VPN connection attempt and decide if they will allow the connection. I am not sure what information is exchanged, but my guess will be the sim card IMSI and using that it looks up some sort of table, and makes a decision based on that.

If Singtel's table for any reason permits only those entries with only 4G subscription, the result will match exactly with your observation. Now we don't know if this is indeed the case, but this scenario matches your description.

Another possibly is the gateway forwards those connection to different backend system depending on whether it is a 4G or 5G subscription, and the one handling the 5G subscription is having some issue (or limitation).

Changing your phone's 5G/4G connection setting will not make a difference in these cases since it is based on subscription.

Understood, this makes sense. That's why changing the setting locally on the phone will make no difference. But now I think we've clearly established that Wifi calling for Singtel on 5G plan doesn't work. I only have one single successful datapoint for Wifi calling on Singtel 4G plan. Maybe if there are others on Singtel 4G, can try also.

 

[bencheongcm]

Something to add, if you do not have IPSec passthrough on your router at home, WIFI Calling is not going to work even if you enable it on yor phone. That is the protocol which is needed for WIFI Calling.

 

[Byfrost]

Hi, is anyone else here using Singtel mobile and using Singtel Wifi calling? Is it still working for you?

My situation is this. The Singtel mobile reception at my place is really bad, most of the time only 1 bar or sometimes can't even get any signal. So all along I have been using Singtel Wifi calling to get around this problem. However, recently (I don't know exactly when) Singtel Wifi calling seems to have stopped working. Even when Wifi calling is turned on, it still shows the network as only Singtel instead of Singtel Wifi Calling.

I ran these simple tests:

• I have 4 Singtel mobile lines at home (3 on 5G plan, 1 on 4G plan). All 4 lines are using iPhone, same iOS version. But the 3 5G lines cannot get Wifi calling, while the 4G line can.
• I brought all 4 lines to another place, using another Wifi network to test, same result.
• Then I used my friend's Starhub 5G line at my place with my Wifi, Wifi calling works on his phone.

So I'm pretty sure the problem isn't with my Wifi or home broadband, and my conclusion is I think the problem is with Singtel. I've called Singtel to get them to look into this, still waiting for their response.

Can confirm as well. Singtel Wi-Fi Calling stopped working for more than a year at my home Wi-Fi (M1 Fiber), I lost count. I'm on Singtel 5G SIM Only plan, using iPhone with latest iOS. Initially it was working daily when the 5G plan was launched.

I wouldn't say stopped working, more like randomly appear for a short while, then disappear after a few minutes. I only see the Singtel Wi-Fi calling Icon once or twice a week at home.

However, on Singtel's Wi-Fi places (i.e. Friend's or Relative's home using Singtel Fiber Broadband), the Wi-Fi Calling appears more often, although not always as well.

 

[HaPpYdAy]

Mine stopped working since early March this year.

3 Singtel Sim Only plans with 5G.
All on different iPhone models. None work.

 

[tohchr]

Can confirm as well. Singtel Wi-Fi Calling stopped working for more than a year at my home Wi-Fi (M1 Fiber), I lost count. I'm on Singtel 5G SIM Only plan, using iPhone with latest iOS. Initially it was working daily when the 5G plan was launched.

I wouldn't say stopped working, more like randomly appear for a short while, then disappear after a few minutes. I only see the Singtel Wi-Fi calling Icon once or twice a week at home.

However, on Singtel's Wi-Fi places (i.e. Friend's or Relative's home using Singtel Fiber Broadband), the Wi-Fi Calling appears more often, although not always as well.

Mine also not working. Tested on both iPhone 16PM and Samsung S25U.. (both phone Singtel lines)