Dataflow Error: Access token has expired resubmit with a new access token

[gp10]

I'm trying to create a transformation dataflow from a staging dataflow. 
The staging dataflow contains a big volume of data and refreshes fine.
In the transformation dataflow I'm trying to group and aggregate the staging dataflow.
I'm getting this error after an hour or so:

[DM_ErrorDetailNameCode_UnderlyingErrorMessage]=<ccon>Access token has expired resubmit with a new access token</ccon> [DM_ErrorDetailNameCode_UnderlyingHResult]=-2147467259 [Microsoft.Data.Mashup.ValueError.Error]=error "Microsoft.Mashup.Engine1.Runtime.ValueException: [Expression.Error] The field 'pbi.error' of the record wasn't found.#(cr)#(lf) at Microsoft.Mashup.Engine1.Language.ValueCreator.CreateValueForThrow(IThrowExpression throwExpr)#(cr)#(lf) at Microsoft.Mashup.Engine1.Language.ValueCreator.<>c__DisplayClass23_0.<CreateValueForRecord>b__0(Int32 index)#(cr)#(lf) at Microsoft.Mashup.Engine1.Runtime.RecordValue.DemandRecordValue.get_Item(Int32 index)#(cr)#(lf) at Microsoft.Data.Mashup.ProviderCommon.MashupResource.TryGetValue(Func`1 getValue IValue& value String& errorMessage)#(cr)#(lf)Record" [Microsoft.Data.Mashup.ValueError.Reason]=TokenExpired

How can I solve this?
Thanks.

[egnvictorfarias]

  Hi, I managed to solve it! 

Despite appearing online, it wasn't working: the problem started after I was 'forced' to change my office365 password, I edited the 2 Gateways and confirmed my credentials.

I just clicked edit and confirmed the credentials. Then I tried refreshing the dataset and it worked.

This must be done for each gateway that has credentials (file/folder/etc)

[feadrian]

I have the same problem, but...

- It happens on Datasets that are using Dataflows
- It happens when my company forces me to update mi Windows sign-on password

It happens as if those Datasets had the old password embedded instead of a one-time validation to access the dataflow, independent of latter changes

The problem is I don't know hoy to solve it
I even tried updating the pbix after refreshing in desktop and still, refresh gives the same error