Why are some phone numbers not clickable?

The System One mobile app allows you to click on a phone number to call or send a WhatsApp or Telegram message.

When a phone number is part of a text, for instance in a free field, the app uses pattern recognition to automatically make phone numbers linkable.

Some users report that local phone numbers in the mobile app don't always have a clickable blue link. This is because the text could not be recognized as a phone number.

When you want to make sure the app recognizes phone numbers, include the international country code.

For instance: +49 (0)30 1214 5480.

When you omit the country code, the phone number might be recognized, but the reliability varies by the length of the number, the way you've formatted the text and if you're on an iOS or Android device.