Can't extend ring time

[Steve]

I've been trying to extend the ring time on my P30 Pro on Sky mobile
(O2) from 20 seconds to 30 seconds.

I enter **61*759*11*30# and get the message
Call forwarding. Registration was successful.

Then I check it with *#61# and get the message
Call forwarding Voice: +44759 after 20 seconds.

I've tried rebooting the phone and switching off wifi to disable
wifi calling, but so far nothing is allowing me to extend the ring
time. Anyone have any ideas I could try? Thanks.

[Woody]

What is the '759' in your sequence? You should be entering a full mobile
or landline number.

You don't say who your SP is - not all SPs permit you to make your own
changes.

[Steve]

It's Sky mobile. 759 is the Sky voicemail number.
Instructions for changing the ring time before diverting to
voicemail are at the bottom of this page under "Voicemail greetings,
settings and help".
<https://www.sky.com/help/articles/sky-mobile-voicemail>

Sky works on the O2 network and ISTR reading somewhere that WiFi
calling breaks sending of MMI codes on O2, so I turned off my WiFi,
but it still didn't work.

[notya...@gmail.com]

On Tuesday, 30 November 2021 at 21:14:42 UTC, Woody wrote:
> On Tue 30/11/2021 20:32, Steve wrote:
> >
> > I've been trying to extend the ring time on my P30 Pro on

>> Sky mobile (O2) from 20 seconds to 30 seconds.

SNIP