MS Reporting Services 2005 - 报告订阅仅在电子邮件中工作

I have an internal customer that only receives his email report from MS Report Services 2005 about 30% of the time. It is not getting caught by a SPAM filter. The report takes about 2 minutes to run. Does Reporting Services give up after 60 seconds? How do I begin to troubleshoot this issue.I have an internal customer that only receives