Salesforce Migration Specialist

Hi,

I have installed Xfiles pro to a sandbox.  Validated the Amazon S3 server location and set up the page layouts, etc as advised.  I have it on the Account, Contact and Task Object.  When I go to attach a file it keeps coming up with the error “Server not responding. Please try again!”.  If i use the S3 browser outside Salesforce with the same credentials I can save a file to the S3 server.  Could you advise what I may be missing?  I have allocated the XFiles Pro Admin permission set ti the user as well.  Is there a remote server setting that needs to be added to Salesforce by chance?

Thanks

Mike