@tetitasdelametr Welcome to the community. Are you talking about the Sqyare reader for contactless & chip readr? if so try this.
1. On the iPhone go to Settings → Bluetooth. If you see an old Square Reader listed, tap ⓘ → Forget This Device.
2. Go to Settings → Privacy & Security → Bluetooth and make sure Square is allowed to use Bluetooth.
3. Completely restart the iPhone.
4. Make sure the reader has a good charge. Square recommends charging it before troubleshooting.
5. Open Square → More → Settings → Hardware → Square Readers.
6. If the old reader appears there, choose Forget This Reader.
7. Choose Connect a Reader.
8. Hold the button on the Square Reader for about 3 seconds and release it as soon as the orange lights start flashing.
9. When the iPhone displays the Bluetooth pairing request, tap Pair.
You want flashing orange lights during pairing. If you get flashing red lights, you've held the reader's button too long and need to try again. Four green lights indicate a successful connection.
If it STILL won't pair
Do a hard restart of the reader: with it charged, hold its button for a full 20 seconds and don't release until the red lights stop flashing. Then turn it back on and repeat the pairing procedure.
Hopefully one of these will get you up and running.
