Setting Up Call Forwarding and Troubleshooting Errors

Setting Up Call Forwarding and Troubleshooting Errors

Introduction

Call forwarding (also known as call diversion) allows incoming calls to be redirected from one phone to another number. This is particularly useful when you are unavailable, busy, or want calls to be forwarded at all times. On Android devices, call forwarding can be set up via the system menu or USSD codes. In Germany, functionality often depends on the mobile network provider, such as Deutsche Telekom, Vodafone, or O2 (Telefónica). Common errors, such as “Unexpected response from network,” occur due to network restrictions or technical issues.

Setting Up Call Forwarding

Call forwarding can be set up in two ways: through the Android menu or using USSD codes. It is advisable to start by restarting the device and ensuring a good network signal.

Via the Android Menu

1. Open the Phone app. 2. Tap the three dots (⋮) or the menu icon. 3. Select “Settings” > “Calls” > “Call Forwarding” (or “Call Diversion”). 4. Choose the forwarding type:

  * Always forward (unconditional forwarding).
  * When busy.
  * When no answer (e.g., after 15 seconds).
  * When unreachable.

5. Enter the destination number and enable the option.

If VoLTE (Voice over LTE) is enabled, conditional forwarding may fail. Disable VoLTE under Settings > Mobile Network.

Via USSD Codes

USSD codes (Unstructured Supplementary Service Data) are key combinations entered directly in the Phone app. They often bypass menu issues and are network-specific.

• Disable all forwarding: ##002# (recommended as the first step).
• Unconditional forwarding (all calls):

 * Activate: *21*DestinationNumber#
 * Deactivate: ##21#
 * Check status: *#21#

• When unreachable:

 * Activate: *62*DestinationNumber#
 * Deactivate: ##62#
 * Check status: *#62#

• When busy:

 * Activate: *67*DestinationNumber#
 * Deactivate: ##67#
 * Check status: *#67#

• When no answer:

 * Activate: *61*DestinationNumber*Time# (Time in seconds, e.g., 15)
 * Deactivate: ##61#
 * Check status: *#61#

After entering the code, press the call button. Wait 10–20 seconds for confirmation.

Common Errors and Troubleshooting

Error Description

The error “Error in call settings – Unexpected response from network” (or similar, “Unexpected response from the network”) occurs during setup and indicates communication issues between the device, SIM card, and network.

Causes

• Network or provider restrictions, e.g., in prepaid plans or with VoLTE.
• Weak signal or network switching (from 4G/5G to 3G).
• Preconfigured forwarding to voicemail (e.g., O2: +491793000400).
• Device issues, such as outdated software or a faulty SIM card.

Troubleshooting Steps

1. Disable all forwarding with ##002#. 2. Restart the device and toggle airplane mode on/off. 3. Disable VoLTE: Settings > Mobile Network > Turn off VoLTE. 4. Reset network settings: Settings > System > Reset > Reset Mobile Network. 5. Check the SIM card: Remove, clean, and test in another device. 6. Contact the provider if the service is not enabled.

If the error persists, test with a different SIM card or device.

Provider-Specific Information

In Germany, options vary by provider. Call forwarding is usually free but may be restricted in prepaid plans.

Deutsche Telekom (incl. Congstar)

• Voicemail: **62*3311# for forwarding to voicemail.
• Frequent VoLTE issues; Hotline: 0800 33 01000.
• In prepaid: Often possible, but check in the customer portal.

Vodafone (incl. CallYa)

• Unconditional forwarding usually possible, conditional forwarding restricted in prepaid.
• Voicemail: Call 5500, then 271#.
• Hotline for activation: Check in the MeinVodafone portal.

O2 (Telefónica)

• Prepaid: Often only unconditional forwarding possible; conditional forwarding fails.
• Voicemail: **004*333#.
• Hotline: 0176 888 555 00; manual activation possible.

Other Providers

For discount providers like Aldi Talk (Telekom network) or 1&1 (O2 network), similar rules apply as for the base network. Check in the customer portal whether the service is included.