Web Interface Not fully Loading

I' ve got an issue with a 20C where every week when I log into the web interface I get the header bar and page background of the interface but the interface is completely blank. I can log out successfully by the log out button in the header bar but that is it. Other than that the system seems to be running normally. I tried a restart from CLI but it hangs and I eventually have to unplug the unit to reset it and the web interface comes back. My question: Is it possible to restart the web server or something so I don' t need to physically go and unplug the firewall to get the web interface back? Also, any ideas why this may happen? This unit has been running fine from day one. The only thing I changed before the issue started is I added a site to site vpn (fortigate to fortigate) but the vpn is not currently enabled. Version: Fortigate-20C V4.0,build0511,120110 (MR3 Patch 4) Just looked at sys top and I see 11 instances of httpd running. None have overly high cpu or memory usage. I tried killing these but nothing changes. I tried to exec reload httpd but i get an error back, it looks like this isn' t the correct command. Any help would be greatly appreciated. Thanks!