Hi, this is Klaytn API Service Help Center.
Regarding the error message that you encountered while using free tier, we kindly refer to the information below for the solution.
KAS currently provides 10,000 API requests per day for our free-tier clients. But for APIs that require a transaction like “Transfer”, you have to set the fee payment option.
Otherwise, you may see an error message like below, even if you have requests left:
_message: ‘a free-tier user does not have access to the API’,
There are two things you can do to prevent this:
(1) Using a KAS Global Fee Payer Account
You need to at least have a Starter plan.
(2) Using a User Fee Payer Account
You can update the options of the contract to use an account with sufficient balance.
To find out more, please refer to the Fee Payer Option section of the KAS Reference Documentation.
Klaytn API Service Help Center