BigQuery Access Denied: Permission Issues

[GreenWave1234]

Hey all, I'm trying to set up a data transfer in BigQuery and have continuously ran into the same issue for multiple hours while trying to move my data from a GCS bucket into BigQuery.

Here's the censored version of the error:

Failed to start job for table AR with error PERMISSION_DENIED: Access Denied: Connection ##########.us-central1.#######: User does not have bigquery.connections.delegate permission for connection #######.us-central1.#######.

I have repeatedly added the bigquery.connection.delegate permission as well as other permissions to the service account performing the data transfer, the service account handling the external data connection, as well as the users attempting to execute the data transfer. I have still gotten the same exact error, every single time.

Here's what the service account doing the transfer looks like, minus a custom role that is essentially for BigQuery and GCS admin as well as the bigquery.connection.delegate permission.

Here's a user account, again minus the custom role.

And here is the service account roles responsible for the data connection

Any help would be much appreciated!