UK 5800 sim-free, red, on T-mobile payg:
When you try to make a call, a message says that your voicemail service is being updated and to please try again in a few minutes. Sure enough, a 'configuration message, please delete' comes through, despite the fact that voicemail was already correctly configured. The problem is intermittent, but is a pita when you want to make a call and gradually fills the SIM memory.
Anybody else come across this or is it purely an operator fault?
That sounds like a network operator fault, I would definitely start by contacting them to ask about it.
Yes, I think so; not a handset issue at all. I think it may have something to do with setting the diverts on the handset before the voicemail box settings had been set. I turned all the diverts off then set them again.
It made me realise that I actually know very little about how GSM works. I would have thought that if all the diverts were turned off, then the phone would just ring and ring if you didn't answer. But in actual fact, it switches to voicemail in just a few rings, whereas the divert settings allow up to 30 seconds before diverting to voicemail. Weird.