Hello All,

I am trying to test run a nintex app (DocGen/Drawloop) and it works fine in production but I cannot get it to run without an error in sandbox. 
Nintex customer service told me the following when I shared the errors with them:
"For the newest error you provided, that is actually a Salesforce error. This is what our Error Browser mentions: Unable to serialize property of 'records' on type common.api.soap.wsdl.QueryResult Error Id: 821496744-32366 (816038562). You will need to reach out to Salesforce to confirm what exactly is occurring."

Here is the code I am using for the button (it's exactly the same as the production Org) and showing No Syntax Error:

{!REQUIRESCRIPT("/soap/ajax/25.0/connection.js")} 

//GRABS THE IDS FROM THE LIST VIEW 
var selectedIds = {!GETRECORDIDS($ObjectType.Candidacy__c)}; 

// CREATES AN ARRAY 
var records = []; 

// INCREMENTALLY LOOPS THROUGH THE ARRAY WHILE CHECKING A CHECKBOX CALLED RUN DDP NEXTGEN  
for (var i = 0; i < selectedIds.length; i++) { 
var record = new sforce.SObject("Candidacy__c"); 
record.Id = selectedIds[i]; 
// If this field is not a checkbox, the value (1) will also need to change. 
record.RUN_DDP_NEXTGEN__c = 1 
records.push(record); 
} 

// ERROR CHECKING 
try 
{ 
var update = sforce.connection.update(records); 
if (update && update[0] && update[0].errors && update[0].errors.message) 
alert(update[0].errors.message); 
else 
alert('Your request'+(records.length == 1 ? ' is' : 's are')+' being processed.'); 
} 
catch (err) 
{ 
alert('An error has occurred. Please try again. '+err); 
}


Any help would be greatly appreciated.

Thanks,