Crystal Report Exporting to CSV taking longtime

HI Experts,

We have an issue in one of the Crystal Report, Report has around 900 records and Report is available in InfoView

When we are trying to export to CSV from infoview, an error is appearing "bad gateway the proxy server received an invalid response from an upstream Server",

And also we try to export CSV from source file (means rpt file from Crystal Report tool), It is taking much time almost 2 hours.

Any Idea why this is happening, your help is much appreciated .

BR,

Venkat