Reports Slow or Not Generating

Reports Slow or Not Generating

I noticed some PMP reports, the XLS or PDF report will never generate. Sometimes after rebooting, they will, but other times I try to run a report and it just sits there working but never does anything. Other times the XLS report will generate but not the PDF report. We dont run reports like this often but we got asked for some reports and this was happening. I was able to reboot the server and get the reports but after awhile its back to the same thing. I can generate the report, but exporting it to XLS and PDF don't always work. Is there something I can check for this? 
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