Power Bi refresh error

Hi lbendlin 

I just wanted to give a brife explnation on my scnerio,
Initialy we  load only 2 months of data on the materialised views and publishing the report. Once the report is published we ask data engineers to load the remaining data which is 2 years of data nearly 8gb. After the 2 years of data ingested, trying to do the refresh on power bi service using gateway but is is throwing an error. Please suggest what should follow here? And also, for an example, if we're loading the 2 months of data initially. And then adding 3 more months of data additionally on the same view once after the report published with 2 months data. Is it possible to do refresh for newly added data without refreshing the last added 2 months data.
Kindly help