HTTP server hangs


I noticed that in some occasions the HTTP server stops operating. When this happens, I am still be able to connect to the digiconnect via tcp. After a timeout of approximately 1 minute the HTTP comes back online again.
I can repeat this problem simply by setting a meta refresh tag of 10 seconds. After 9 or 10 refreshes the server will stop.
Anyone any idea what might cause this ?
Are there any debug or status functions I can call to verify correct operation of the HTTP server ?

thanks in advance!