Sometimes, it happens to a few of our battery cases, it's more like a compatibility issue with the phone system. 

We have some suggestions for help.

To check if the phone has a moisture issue or not:

1. Use a soft dry cloth to gently wipe your phone, and shake it while keeping the charging port down. Then place the phone in the open air close to the fan.

2. If you have a hairdryer, use it to blow mildly hot air at slow or moderate speed into the USB/lightning charging port from different angles for a couple of minutes to ensure that moisture dries up.

3. Blow compressed air at low pressure into the USB/lightning port.

The phone system may also cause it. If there is an alternative upgrade Android/iOS option on your phone, you can try to upgrade it and check if the issue still happens.

If the problem still exists, we'd love to provide you a warranty replacement. Please send an e-mail to infor@zerolemon.com with your order number. Thanks.