If you’re not getting and notifications or calls, open your Control Centre and check there is no red cross or red phone with a line through it and the word disconnected showing.
When it reconnects with the phone a green phone icon will appear.
Try the below steps to reconnect;
If it still fails, unpair and repair your device following the below steps;
For more info, see https://support.apple.com/en-gb/HT205025
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