Fixer.io not working

Hi, I’m using latest release v11.0.1, I’m trying to get the Exchange rate for CRC - USD, however, it’s not working.

Error message: Unable to find exchange rate for USD to CRC for key date 2018-09-21. Please create a Currency Exchange record manually”

If I use fixer.io API using curl I’m able to get the Exchange rate

Is there any place where we should put the API key for fixer.io to work?

Thank you!