Check that:

• Your service is active
• There is sufficient balance available for outbound calls
• Your device is configured correctly
• You have an active internet connection

The issue may be caused by:

• A disconnected VoIP device
• An internet connectivity problem
• Incorrect SIP settings
• Active call forwarding
• A temporary technical issue with the service

You can log in to your account at my.modulus.gr and check the status of your service, as well as your subscription expiration date.

Check the following:

• The SIP account username and password
• The SIP server address
• Your internet connection
• Firewall or router settings
• Any recent changes made to the device configuration

This usually happens when:

• The internet connection has been interrupted
• There is a power issue affecting the device
• The SIP settings have been changed
• There is a problem with the local network configuration