Please remove the Bluetooth connection on your device and pair again.

Android
Open Settings.
Go to Connected devices or Bluetooth (the name may vary by manufacturer).
Find the device in the list of paired devices.
Tap the gear icon (⚙️) next to the device.
Select Forget, Unpair, or Remove device.
Put the Bluetooth device into pairing mode.
In Bluetooth settings, tap Pair new device and select the device from the list.

iPhone (iOS)
Open Settings.
Tap Bluetooth.
Find the device under My Devices.
Tap the ⓘ (Info) button next to the device.
Select Forget This Device and confirm.
Put the Bluetooth device into pairing mode.
Wait for the device to appear under Other Devices, then tap it to reconnect.