NIGHTHAWK M5 5G WiFi 6 Mobile Router (MR5200) freezes and does not connect Case #46244255

About 18 months ago I purchased the NIGHTHAWK M5 5G WiFi 6 Mobile Router (MR5200). I live in an area with poor coverage. That's why I used it sporadically to connect to a 4G (LTE) network. However, I decided to increase the range and stability of the connections. I bought the OMNIDIRECTIONAL MIMO Antenna from NETGEAR.
The router only worked correctly once after connecting this antenna for the first time. He found the orange network, speed tests were good at 80-90MB / s. Unfortunately, it stopped working properly after that.
If I turn off the router, connect the antenna and turn it on again, the router freezes - first it displays the NETGEAR welcome logo, then the image changes to 5G and it freezes. It does not go any further. Not logging in. It does not respond to reset (button on the back). It turns off when the battery is removed and the same situation occurs when turned on again. This happens both when the antenna is connected and when it is disconnected. It hangs and it's over.
I applied for technical support to NETGEAR but was refused. They claim that the equipment was not purchased from their authorized sales network and I cannot take advantage of the two-year warranty. This is very bad behavior from NETGEAR. I considered this company a leader in the router market. Unfortunately, they turned out to be not very professional. Now I have a router that is not working and I cannot get support.