It may happen that, as soon as you dial the phone number you want to contact, on the screen of your smartphone appears the message "Call ended".

Usually this message does not appear immediately, but after an annoying waiting time that can exceed even 1 minute. Very annoying, especially when you are in a hurry to contact that number.

Solutions:

Most likely: The smartphone is outdated. It would be better to update firmware and software. Turn the smartphone off and on again.

Likely: Phone card. The chip is dirty or the card is wrongly inserted. So you need to clean the chip and reinsert the phone card. It's always better to restart the smartphone.

Fairly likely: Lack of signal in the area where you are.

Less likely: The owner of the number you are calling has put your number on the black list.

Unlikely and rare: The firmware of your smartphone is outdated or the firmware update failed.

Good luck!