Report not refreshing due to the Power Query Data errors, but works after I refresh the preview data

I suppose it depends on the nature of the error but this can happen because the preview only loads 1000 rows so if the error occurs later it won't show in preview

Anonymous 

this seems to be a data conversion error. Since powerquery does not download the full data so may not be able to face the error in the powerquery but after the full data is loaded then this error might be occuring. Please check if your date and numeric column has any non-date or non-numeric values which causing this error to appear. You could remove auto conversion from value to date  in the powerquery and try to do in the powerbi desktop. 

also refrer to below links for some guidence. 

https://docs.microsoft.com/en-us/power-bi/connect-data/refresh-troubleshooting-refresh-scenarios#:~:text=of%20your%20credentials.-,Data%20refresh%20failure%20because%20of%20password%20change%20or%20expired%20credentials,an%20update%20of%20your%20credentials

I have the same issue but my load in powerBI service is "working"

I will test the one parrallel load option 

Thank you

Sometimes i discover that my review loads are not available anymore

(look at the crzay date right bottom corner!!)