Z1 show Message "cambiar a llamada" "change a Call"

[bedto]

Hi, when I make a call, sometimes the call is not done, I mean when I pressed the button call, I see the message "change a Call" and I have to wait for the cell phone make the call
This not happen everyday, but is constant, I try format the cell and install android. But not working, it's only happens with lollipop.
Please helpme

[Uliwooly]

@bedto

Does this happen when you call someone hang up > call right back?

[Phy]

Try to clear the phone app data.

How to clear data on apps.
From your Home screen

1. Tap the Application screen icon.
2. Find and tap Settings > Apps.
3. Swipe to the All tab.
4. Find and tap on the phone app.
5. Tap Force stop > Clear data.
6. Restart the phone

[bedto]

Happens when I make calls, and when I receive i cant answer, shows an notification in order tu answer the call, and then i presseed answer but the phone no answer the call

[bedto]

I try to clean Phy, and i see two apps for phone apps, so i clear both app data

[bedto]

And dont work

[Phy]

Do experience the same while on safe mode?

How to boot on safe mode.
http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008

[bedto]

I don't try the safe mode, because I receive an update for the cell phone and the problem was solved

Thanks