The interface type should be populated automatically by the connection so you cannot "change it" in that sense. When connected by cable it will be a port, when wireless it says so. [Don't make it multi-homed; e.g. with multiple connections to hub active at the same time: that is bad idea.]
If you cannot connect to hub wirelessly and the print server and wifi SSID are correctly matched for security details and type then is it because hub has wireless mac filtering active - if the hub has lost the details of print server mac card then you may be being locked out from connecting? You may need to temporarily disable this to allow first time connection then re-activate it or provide the details manually [my experience of that is "mixed" so recommend let hub perform it with temporary deactivation of the feature.]
When hub rebooted it could have reset itself to factory defaults: I have on occassion seen my hub lose its settings. It is also possible in that time frame that the hub firmware was updated by BT. This might have reset something.
I assume the print server is set to obtain connection details from the hub too. It should be set up for dhcp client but you can configure the hub to then allocate a static address, if necessary.
Could also be hardware failure of print server wifi card, of course. Can you validate that the server is actually "live" with some sort of wifi sniffer tool or network monitor?
