The client must be updated to https://github.com/geosolutions-it/MapStore2/commit/b6357f26b744edb7a2f6521c7586c4563d7abda2 to solve the issue with the DownloadEstimator request.
The client must be updated to geosolutions-it/MapStore2@b6357f2 to solve the issue with the DownloadEstimator request.