Apex SDK - Receiving Error "message":"Invalid parameters.","code":400,"name":"Validation Error"

We were successfully sending transactions and documents to OneSpan until the start of this week when we started receiving the below error. I have also put the invoking code below, it is based on the Apex SDK. It's a weird error as this was working on Friday..

CallOut:

HttpRequest[

Endpoint=https://sandbox.esignlive.com/api/packages/2c-NU-6SlNqyIhDT2Uhew9hueus=/documents, Method=POST

]

Error in Full Text:
OneSpanRESTAPIHelper.OneSpanRestAPIHelperException: Error creating OneSpan package with documents: 400 - Bad Request - {"technical":"Unexpected Content-Disposition value for parameter 'name'","messageKey":"error.validation.invalidParameters","message":"Invalid parameters.","code":400,"name":"Validation Error"}

Invoking Code:

OneSpanSDK sdk = new OneSpanSDK();
        
OneSpanAPIObjects.Package_x pkg = new OneSpanAPIObjects.Package_x();
pkg.name = 'Test Subject ' + DateTime.Now();
String packageId = sdk.createPackage(pkg);
Cust_Object__c dsRec = [SELECT Id FROM Cust_Object__c WHERE Id = :dsId LIMIT 1];// Gets the document
// Create Documents for Transaction
Attachment att = [Select Id, Name, Body, ParentId From Attachment Where ParentId = :dsId];
Map<String,Blob> doc = new Map<String,Blob>();
doc.put('Sample Document', att.Body);
        
OneSpanAPIObjects.Document document = new OneSpanAPIObjects.Document();
document.name = att.Name;
document.id = 'document1';
String resp = sdk.createDocuments(packageId, document, doc);