R7000 Remote Management no longer working

For a long time, I have used the Genie app on my iPhone to manage my Netgear R7000 locally and remotely. Local still works, but for the past few weeks Remote Management does not; it fails with a password message even though that same password works if I'm local. When I'm remote, I use the Genie phone app as follows:
- Login to Manage
- Remote
- Select a router to manage (and it shows my R7000)
- Enter your router admin password
- Login
Then it fails with this msg: "Login Failed. Enter the correct admin user name and password for your Netgear router". I've clicked on the "eye" icon to view the password in the open, so I'm sure it's correct. And the same password works locally. Also, Remote Management is enabled on the router; I've double checked on both the phone Genie app, and directly on the router when I'm home. I have tried the default "password" too. I've used the Shields Up website to verify that the Internet address of my router is reachable, and port 8443 is open. I've rebooted my modem and R7000 several times. I have NOT yet reset the R7000 to factory defaults because so many other people have posted that it didn't solve anything, and it will be a lot of work to reconfigure from scratch, and verify all my devices retained all their functions. So...before I do that, does anyone have any ideas? Thanks!