Effects of Firewall response timeout increased.

So I have a firewall that is acting as a web proxy for users, the issue is whenever users try to generate report from a cloud application, It fails and I get an error message that says "response timeout 5xx error code"

After further investigation, I found out that the firewall http proxy response timeout is set to 60seconds. I increased this timer to an hour and users were then able to generate reports that took very long to generate (report generating could take as much as 20minutes)

However I am not sure the inherent risk of doing this, all I could think of is I may have increased possible sessions the firewall will hold with unresponsive web servers, and may overwhelm it's performance.

Besides this effect, I want to know what are the possible risk I may have incurred by increasing the response timeout from 60secs to an hour.

Thanks