make sure your Google map keys are created with verified cards; the plugin setting only checks the pattern; it does not check whether you have an active google map key or not.
Billing Account – Google now requires a credit or debit card on file for Maps to work. You are given $200 free credit each month which will essentially mean the service is still free for the majority of users.
when you are setting your keys, make sure these APIs are enabled.
nothing is limited from the plugin end; if the key has the above API enabled and it will display a map, the map says it’s for development purposes, which indicates
You have not enabled billing on your project, causing this error. You must enable Billing on the Google Cloud Project.
On following link Search for : BillingNotEnabledMapError