You will see this message when you tried to check the shipping fee estimation or failed to check out. There are few factors that caused customers are not able to proceed with shipping method selection.
1. Kindly ensure that weight is inserted for the products at
Products -> Edit Product -> General -> Weight.
2. Kindly ensure that shipping requirement is enabled for products at
Products -> Edit Product -> General -> Advanced -> Require Shipping: Yes.
3. Kindly ensure at least one shipping method is enabled at
Settings -> Shipping -> Edit Shipping Method -> Status: Enabled.
4. Kindly ensure that Weight Class is applied correctly for the enabled shipping method at
Settings -> General -> General -> Standards & Formats -> Weight Class.
Once you have done each of changes, please click Save button and Clear Cache (green button) to have all changes on Store Front.