Sporatic Error, using the API.

Hello Everyone. 

I have another weird error.    the spread sheet I am making is 35 columns across and 270 rows down.   I do batch updates exclusively.  And I also time my updates to the most updates are 160 a minute to not overload the Server(a 200 ms delay between updates).   

sometimes mid way through the updates Im getting 

• Invoke-WebRequest : { "errorCode" : 1006, "message" : "Not Found", "refId" : "td1ey3p82fb4", "detail" : { "index" : 0, "rowId" : 7863688549951364 } }
• At <REDACTED>\Powershell\Smartsheet\SSUpdate2.ps1:248 char:27
• + ... esponse2  = Invoke-WebRequest -Uri https://api.smartsheet.com/2.0/she ...
• +                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
•     + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebException
•     + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand    

But if I wait a second or 2, it runs through no problem. ???

Am I pumping too much data through?

any help would be appreciated.