Magento 2 shipping troubleshoot

I am looking for a Magento 2 expert to troubleshoot my free shipping function which was working fine before. Customers with orders over 100 got free ship and they could use product discount coupon code. Now suddenly its charging shipping on orders over 100 too. Im trying to bypass with setting cart rule but then it takes it as coupon and customers are unable to use actual product discount codes.

Ideal skills and experience:
- Expertise in Magento 2
- Experience troubleshooting complex issues in Magento 2
- Excellent communication skills to explain the issue and proposed solutions to me in a clear and concise manner.
-Preferably remote help without system access.