Data Source Error with dataflows

I have a report with about 35 sources, all dataflows. The pbix sits at just under 9GB and cannot be refreshed all at once; it runs out of memory in the Power BI service. I've seen several different versions of the same error in the service when attempting to refresh the dataset. Here is the latest one:

Data source error{"error":{"code":"DM_GWPipeline_Gateway_InvalidConnectionCredentials","pbi.error":{"code":"DM_GWPipeline_Gateway_InvalidConnectionCredentials","parameters":{},"details":[{"code":"DM_ErrorDetailNameCode_UnderlyingErrorCode","detail":{"type":1,"value":"-2147467259"}},{"code":"DM_ErrorDetailNameCode_UnderlyingErrorMessage","detail":{"type":1,"value":"The credentials provided for the PowerBI source are invalid. (Source at PowerBI.)"}},{"code":"DM_ErrorDetailNameCode_UnderlyingHResult","detail":{"type":1,"value":"-2147467259"}},{"code":"Microsoft.Data.Mashup.CredentialError.DataSourceKind","detail":{"type":1,"value":"PowerBI"}},{"code":"Microsoft.Data.Mashup.CredentialError.DataSourceOriginKind","detail":{"type":1,"value":"Web"}},{"code":"Microsoft.Data.Mashup.CredentialError.DataSourceOriginPath","detail":{"type":1,"value":"https://api.powerbi.com/powerbi/globalservice/v201606/clusterdetails "}},{"code":"Microsoft.Data.Mashup.CredentialError.DataSourcePath","detail":{"type":1,"value":"PowerBI"}},{"code":"Microsoft.Data.Mashup.CredentialError.Reason","detail":{"type":1,"value":"AccessForbidden"}},{"code":"Microsoft.Data.Mashup.MashupSecurityException.DataSources","detail":{"type":1,"value":"[{\"kind\":\"PowerBI\",\"path\":\"PowerBI\"}]"}},{"code":"Microsoft.Data.Mashup.MashupSecurityException.Reason","detail":{"type":1,"value":"AccessForbidden"}}],"exceptionCulprit":1}}}

I'm not sure how to diagnose the problem. How can there be credential problems when all sources are dataflows? When I go to select Gateway connection to set up refresh I use "PowerBI" and if I open Data Source Credentials I see "Power BI (admin has granted access, credentials are not required)."

Since this file runs out of memory on full refresh I am trying to set up incremental refresh on 5 of the tables. I was following along to a Guy in a Cube video about manually refreshing partitions but could not get past attempting to refresh the dataset after initial upload.

Any help is appreciated.