Matek F405 Wing / Inav / BN 880 - many GPS failures 

Find the way to either or ... move the GPS antenna as far as humanly possible to the controller OR.... you can find the way to twist the tar of all the wires that go in to the controller and wrapp it up in aluminum foil... " I put packing tape in one side.. the one that have contact with the controller

make sure the baud is right, try auto baud

Eso me pasa a mi con una maten 411 con la 220 y la 880 y nadie me supo decir nada