iPhone field test mode - unable to connect your call

[trial812]

Hi folks. 
I’m trying to run a field test using my iPhone 15. 
Using the normal *3001#12345#* method. 

All I get is a recorded message saying unable to connect my call at this time. 

Does anyone know if EE maybe don’t allow this on their network? Or have I got the dial string wrong? 

Cheers. 

[bristolian]

This provides an onscreen engineering view, not a voice call.

[Chris_B]

@trial812  I’ve just copied and pasted your field test mode number and put it on my iPhone and it worked.  

[trial812]

Thanks @Chris_B - that’s good to hear. 
I’m going to try this is different areas of the countryside today to see if it’s just an oddity with my phone, or my area, or range to a tower (I’ll pass very close to my tower later on my travels)
At least I definitively know that that string is correct and it’s not blocked by EE or anything like that. 

Could be a rural Scotland thing - and too far away from the tower or something. 

I’m  typing this from the same phone, indoors, with a pretty rubbish 4G signal, but it will still send. 
So the diagnostic *should* work outdoors  

[bristolian]

Nothing to do with your signal strength, or where your serving site is.

[trial812]

Thank you @bristolian . That’s good to know. 
This begins to narrow it down to being specific phone config or something. 

And the answer was …. If it’s in your contacts as a ‘contact’ that initiates a call, vs manually typing it in to the screen.