can't logon to router locally without reboot and using cable

[MikeFT]

I have R7300 AC1900DST routers in 2 homes. Work pretty well and about 2 years old.  The problem with both is that I cannot easily access the router to make firmware upgrades and to set port forwarding etc.  I have tried the apps on my android phone and on the PC but the only way I can get into the router is after a router reset and running a long ethernet cable.  Surely this should be the simplest of tasks and as it is happening in both locations, this sounds like an issue that is not caused by me. Any help would be appreciated as both are out of warranty.  If I can't solve this I will have to buy two new routers from ma different brand as it is not something I can live with.  Thanks

[michaelkenward]

Same basic questions as here with your other conversation:

2.4 does not work 5GHz does - NETGEAR Communities

They are also relevant to this issue. My guess is the modem in front of the routers.

If you cannot login to your router | Answer | NETGEAR Support

Do you really own an A7000?