Question : <a rel="nofollow" href="HTTP" target="_blank">HTTP</a>: 407 proxy authentication error when trying to run reports.

In our application we have reports that our accessed off of the SRS reports server and viewed using the report viewer. We put these reports in about 7 months ago and have had no problems but all of a sudden no one is able to view the reports... The error message is; 407 proxy authentication required . Now this is at a client site and of course they tell us that nothing has changed. What could they have done to cause this problem? How do I correct it?

Answer : <a rel="nofollow" href="HTTP" target="_blank">HTTP</a>: 407 proxy authentication error when trying to run reports.

could it be that they changed the internet explorer network settings and added a proxy server?
Because that is the classic error message when you do that and forget to exclude the report server (to make it a local server that is addressed directly)