If you can send send (upload) data OK, but cannot download data, you might still experience a combination of the following issues.

1) The download button appears to do nothing.

2) You click download once but MX records three downloads

3) You see a message "not available on site".

There are a number of things to check. For the full list, click here.

If you have ruled out all other options, then it is likely that your IT group operates a whitelist and your IT group need to give permission to the download servers for MX. 

access1.mymxdata.com (52.16.179.182)
access2.mymxdata.com (54.76.156.182)
access3.mymxdata.com (54.171.93.36)

access4.mymxdata.com (52.19.156.190)