It's rated for 300 Vrms CAT II in 10:1 mode. So 330 Vdc is indeed exceeding the maximum limit. Try a 100:1 probe if you need to measure higher voltages. Since you are likely talking about something directly connected to mains, you should probably consider a high-voltage differential probe for this measurement, since you don't want to clip your ground lead to either phase or null of your mains supply.
There are alternative solutions, like using two 100:1 probes, or connecting the device under test to an isolation transformer.