If your phones are working fine (unless they are registered to a backup 3300 somewhere) then your network port is OK.
Either you are trying to connect your laptop directly to the 3300 which is configured for VLAN tagging (and your laptop NIC is unlikely to support 802.1q frame format, ie, it can't do tagging) so it can't connect, or you have IP addressing issues involving the subnet you are in, the default GWs of the devices, and/or the routing table of the device that is acting as default GW.
How are you connecting your laptop to the 3300?
- physically
- logically (ie, IP addresses and default GWs of both devices)
When the 3300 reboots, it initially comes up as an untagged VLAN, then it resets itself and tags the VLAN on its interface. Having the 3300 VLAN as tagged seems to be the Mitel recommended configuration, but I can't for the life of me understand why.
Whichever configuration you go with, the Mitel interface needs to be set the same as the switch interface it is patched to (either tagged or untagged). The switch interface needs to be tagged/untagged in the correct VLAN for the subnet that is configured on the 3300.