I bought their 21-406 external speaker, but its not working as intended even though its connected to the external alert hole. I there something I can do to make this work or do I need a different brand of weather radio?
I don't have a Midland WR400, so I could be mistaken. But, I see that the WR400 owners manual makes no mention of an external speaker option even though it does mention other accessories ( a strobe, and an external antenna). It may be that the "External Alert Jack" is only intended to drive the External Strobe accessory. Personally, I'd plug a headphone into WR400 headphone jack to to test if a normal set of headphones (with a 3.5mm plug). If those work, then something like a "powered" Computer Speaker Kit would probably do what you want.
Something like this is what I am referring to:
https://www.walmart.com/ip/onn-Stereo-Speaker-with-Volume-Controls-3-6-ft-3-5mm-Aux-with-USB-Power-Cable/803187184?classType=REGULAR&athbdg=L1200&from=/searchNote you need a USB adapter to power that kit. Or choose an integrated unit that has a builtin power supply.Please test the headphone jack before you buy anything else. And if that works, perhaps you could borrow a "powered" speaker to test that, before buying anything.
The 21-406 external speaker looks to me that it expects to have an
amplified signal feed, and it appears that is not available in the WR400. The speaker page says "Compatible with Midland MXT500, MXT115, MXT275, MXT400, MXT500, MXT575, 1001LWX, 5001Z" so you could look at those units.