Dataset refresh failed: internal service error

Hi all,

 I have a dataset published on PBI service that after a couple of days with no problems, stopped to refresh.

The error is:

Last refresh failed: Wed Jun 19 2019 09:38:29 GMT+0200 (Central European Summer Time) 
The last refresh attempt failed because of an internal service error.

The sources of this dataset are 3 different dataflows and these dataflows are refreshed without problems every day.

If I open localli the PBIX file and refresh it in PBI Desktop client it works without problems.

What could be the problem when trying refreshing the dataset on PBI service?

Thank you,

Roberto