I cannot create an experiment within a project nor create a new project because apparently my watson studio doesn't have the right permissions to access/create/delete something in my Cloud object storage instance, knowing that the COS service was created from Watson studio itself.
In case this helps, here is service endpoints information:
Follow the instructions provided in Watson Studio FAQ - https://dataplatform.cloud.ibm.com/docs/content/getting-started/faq.html#iameditor
Also,Looks like you don’t have proper IAM access permission. If you are the owner of the account, you can set the required permissions following the steps in this link. If you are not the owner ask the account owner for the permissions.
For best practices, refer this solution tutorial
Hope this helps