Cannot connect Google Ads to BigQuery
I just started using GCP and can't create a data transfer from Ads. I did all steps by this documentation but I always get an issue without any explanation.
There was a problem saving this transfer config This transfer config could not be saved. Please try again. iq sometimes these two letters change, as far as I remember to 'jk' 
As I understand, you are not able to create your Data transfer from Google Ads to BigQuery using the console.
This error may be cuase because you do not possess all the necessary permissions, as per documentation:
BigQuery Data Transfer Service:bigquery.transfers.update permissions to create the transfer Both bigquery.datasets.get and bigquery.datasets.update permissions on the target dataset The bigquery.admin predefined IAM role includes bigquery.transfers.update, bigquery.datasets.update and bigquery.datasets.get permissions. For more information on IAM roles in BigQuery Data Transfer Service, see Access control reference.
Google Ads: Read access to the Google Ads Customer ID or manager account (MCC) that is used in the transfer configuration.Also, you can set the transfer using the bq command,
bq mk \ --transfer_config \ --project_id=project_id \ --target_dataset=dataset \ --display_name=name \ --params='parameters' \ --data_source=data_source