Printer connection

From the WIFI interface specification i can see it supports 802.11 b/g OR b/g/n depending upon the purchase location. Bottom line it uses the 2.4 GHz frequency and authentication is WPA2 Personal as the most secure so the 2.4 GHz frequency must support WPA 2 Personal. Because of the specifications it appears to be a bit older. There have been a number of users reporting issues with printers that have older WIFI radios. There might be a newer driver for the printer, not highly likely, but worth investigating. The problem could be with the T-Mobile gateway's backward compatibility. I have the Nokia GW not the Arcadyan KVD21 and I have a newer Epson and an 845 AIO which has similar wireless capability. With the 845 all in one it only supports WPA so I only use it as necessary but it does connect on the 2.4 GHz frequency. 

If you have an older router, you have total control over, which you can use to make a work around for the 2.4 GHz WIFI connection and have it make a bridge mode or AP mode connection to the T-Mobile GW then you might be able to get the network connection working. It might be better to just get/use an extender that supports 802.11 b/g/n and not 802.11 ac/ax and try to get it to link to a wireless extender that links up to the T-Mobile GW. There are a number of user responses on the community related to efforts to get older printers to link to the WIFI. Maybe there are yet clues to be found. Reddit is another avenue to explore for answers as well.

If you cant get the WIFI connection to work you could connect to it via USB. The Windows and MAC OS specifications appear to date the printer a bit back to 6-8 years ago so even though it should work with the newer WIFI radios the drivers written for it may not play well with the newer 802.11 ax capable gateway. If you have the Arcadyan GW it could be there where the problem resides as the software for that router/gateway seems to be not as mature as it should be. I doubt that the "MAC Filtering" is the real issue here. 

OK, so I was being a bit conservative on the generation of the printer. Those were initially released in September of 2011 so it might be considered a dinosaur. A newer, more efficient printer with better WIFI security might be in order. If you like Epson the ET-2760 AIO works quite well and is not that expensive. If you need multi tray, or faster printing capability and more features you might step up to the next level. You can fight with an older printer or upgrade and have a secure WIFI connection. Using a USB connection to print to the NX430 could be a reasonable workaround.