ERR_PROJECT_INVALID_PROJECT_KEY: Invalid project key

The specified project key is invalid, either incorrect or already used. The error message will have more details on the exact issue.

This can happen when trying to import a DSS project or bundle.

Remediation

Check the project key, edit it if necessary (if it was manually specified).

Check the source of this archive. If you want to overwrite a project when importing, first delete the former project, then import the other one.