./cloud_sql_proxy -instances=playground-s-11-82539a2d:us-central1:forumdb=tcp:3306 -credential_file=./playground-s-11-82539a2d-0e04d1fb026f.json &
seeing the error
cloud_user_p_e7c46d84@testvm:~$ 2020/12/22 19:09:03 Rlimits for file descriptors set to {&{8500 1048576}}
2020/12/22 19:09:03 using credential file for authentication; email=forumapp@playground-s-11-82539a2d.iam.gserviceaccount.com
2020/12/22 19:09:03 errors parsing config:
googleapi: Error 403: Cloud SQL Admin API has not been used in project 57335710336 before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/sqladmin.googleapis.com/overview?project=57335710336 then re
try. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry., accessNotConfigured