What does the device log say about this issue? I'd also suggest speaking with your mobile carrier in case they blocked/blacklisted the modem from their network. I'm just another user

I'd like to see DNS-over-TLS, DNS-over-HTTPS and DNS-over-QUIC (new protocol) support added to the Archer MR series of 4G routers, if possible. Thanks,

@Yadu If you can, check the logs on your MR600, they might tell what's going on

Question: What do the router's logs say about your problem? (I have a MR600 v2, but it should be in Advance -> System -> Logs) Also, try to update your MR6400 to the latest firmware

In your MR600v1, Advanced -> Network -> Internet -> change the band option to 'manual'

You're trying to update your MR6400v5, but it's telling you that the file is not correct? Did you try to redownload the file again? it sounds like you got a bad file or the file got corrupted somehow