We are trying to do Bulk Upsert for Contacts and map all the new contacts that are are upserted with an existing Account Id. So while preparing the CSV we are using Account.Id and the value is the actual Id of the account for all CSV records. However I seem to get an error 
INVALID_FIELD:Field name provided, Id is not an External ID or indexed field for Account:--

As per the documentation https://developer.salesforce.com/docs/atlas.en-us.api_asynch.meta/api_asynch/datafiles_csv_rel_field_header_row.htm any indexed fields can be used. And Describe response for account clearly says idLookup property for Id field is set to true. Can anybody help why this is failing?

We are using Salesforce Streaming API to receive events based on Push topics and for platform events. Initially at subscription Streaming API works fine listening and delivering events. However after a period of around 12-24 Hours the channel gets disconnected. At this point the last incoming message from salesforce was :

{ channel: '/meta/disconnect' }
incoming
{ clientId: '5rw1bxn4jzyed3vhbcjnpkwb2fsd',
advice: { interval: 0, reconnect: 'none' },
channel: '/meta/connect',
id: 'k1',
error: '403::Unknown client',
successful: false }

With this error the underlying Faye client believes there should not be any reconnection and stops listening to channel (No more connection handshake). From the documentation we understand the reliability of message due to load, but complete disconnection is unexpected.

Background : We are using Node JS npm module https://github.com/kevinohara80/nforce for working with Streaming APIs. We were using Salesforce API version 34 earlier, later with the need to support Platform Events we planed to use the API versions 37 and above(41). However only with new apiversion we are seeing this disconnection whereas the earlier 34 version is still working fine. Also with version 34 many events were not generated due to unsupported fields like address etc.

We are trying to do Bulk Upsert for Contacts and map all the new contacts that are are upserted with an existing Account Id. So while preparing the CSV we are using Account.Id and the value is the actual Id of the account for all CSV records. However I seem to get an error 
INVALID_FIELD:Field name provided, Id is not an External ID or indexed field for Account:--

As per the documentation https://developer.salesforce.com/docs/atlas.en-us.api_asynch.meta/api_asynch/datafiles_csv_rel_field_header_row.htm any indexed fields can be used. And Describe response for account clearly says idLookup property for Id field is set to true. Can anybody help why this is failing?