What does this error message mean - 'Invalid combination of dimensions and metrics! Selected dimensions and metrics cannot be queried together, please make a different selection. Learn more'

This message appears when the selected dimensions and metrics are incompatible and cannot be used together to fetch data. To get analytics data, the right combination of them is required. Please check this documentation to see and try all the values that can be combined in the same query.

How can I filter the analytics data by campaign-level traffic?

To view campaign-level data, you'll need to include the dimension 'Traffic sources' as a campaign and then select the 'Add filter' option to check for a particular campaign.