Scheduled data refreshes failing

[Anonymous]

Hi All, we have Power BI Report Server January 2020 (15.0.1102.777) and since about a week ago our scheduled data refreshes have been failing, these are connecting to on prem SQL server sources... the error is :

Error Failed to refresh the model, Exception Microsoft.AnalysisServices.OperationException: Failed to save modifications to the server. Error returned: 'Could not load type 'System.Web.Script.Serialization.JavaScriptConverter`1' from assembly 'Microsoft.Mashup.Shims, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.. The exception was raised by the IDbConnection interface.
A connection could not be made to the data source with the Name of '88e355fa-29a7-4e7a-ae56-a6fe1e11b84c'.

Ive tried it on all our environments and get the same error; any help? this worked until about a week ago... Thanks 

[V-pazhen-msft · Accepted solution]

@Anonymous 
I didn't not find similar issue in the known issue list. Try reinstall the newest version of pbirs.

You should also stick to the newest version since new batches could cause unexpected issues for old version.

Paul Zheng _ Community Support Team