Voicemail setup to change delay not working

[ChrisIB]

The delay on my phone (Realme GT) before voicemail kicks in is the default of 15 seconds.

I tried to use:

**61*901*11*30# then simply press 'call'.

to set it to 30 seconds (after disabling wifi calling) but it gives an error of:

Call forwarding

Connection problem or invalid MMI code (0)

I rang support twice and they said would do it from their end, within 48 hrs, but it is still 15 seconds. Is there any other way to do it?

[MI5]

@ChrisIB 

You said after disabling wifi calling.... did you also turn off wifi as the mmi codes need to be sent over gsm.

[ChrisIB]

Yep, wifi was also off.

Might it be the phone? it is pretty standard though, Android 12

[MI5 · Accepted solution]

Unlikely to be the phone @ChrisIB 

It's a common issue with O2 unfortunately.

If you message O2 on Facebook (https://o2uk.co/O2CFB) , Twitter (https://o2uk.co/O2CTW) or Instagram (https://o2uk.co/O2CIG) , they should be able to help you with this
Thanks