iPhone iMessage goes green or won’t even send while on phone call...

[CoachMike43]

While I’m on a phone call and I try to send an iMessage, when not connected to WiFi, the message either goes green or it doesn’t send after hitting the send arrow.
It was happening on my iPhone 10 but just last month I got the iPhone 11 and set up as new.
I spoke with Apple engineers and At&t...
Is anyone experiencing or can help.
Thanks

 

[badatusernames]

Does your plan allow data while on a cellular call?

 

[CoachMike43]

Does your plan allow data while on a cellular call?

Yes I have voice over LTE. I have gone to Apple and AT&T multiple of times and spent hours upon hours on the phone

 

[DeanCorp]

Tried another persons sim in your phone?

 

[Vlad Soare]

I'm not sure it's an iPhone or iOS issue. I suspect it's your carrier that blocks internet access while on a call. Have you tried opening a web page in Safari during a call?

 

[danmart]

This sort of stuff varies by your cell provider, but on mine (UK EE) there is a setting that lets me turn VoLTE on or off. Maybe it has become flipped for you?

On my device it’s found here:

Settings > Mobile Data > Mobile Data Options > Voice & Data > 4G, VoLTE On