Why are incoming calls routed to voicemail although I press"accept"?

[iMore Question]

Phone rings. I press "Accept" and say "hello". Caller does not hear me. Their call goes to voicemail.

 

[SwitchBeach]

What device?
What carrier?
What country?
Do you have a strong cellular signal?

 

[Larry Cook1]

Hit your phone icon and go to keypad. On the keypad hit ##update# and hit talk. It will say starting update. Hit ok. Then it will say service update complete. Hit ok. Problem should be solved.