Well, this is new and doesn't at all smell like finger printing
For context: I'm already logged in on my phone (and this PC has logged into FB before also). So, how does that work, exactly? Log out, try to log in from phone...same issue, as now BOTH devices are logged out?
Hmm. Near as I can tell, this is due to clearing cookies recently / history. Having said that, I've cleared cookies thousands of times before and been able to log in just fine. Which therefore suggests...what.. policy change server-side, not a coincidence? I'm on the same hardware, same browser, same IP. FB appears to have changed what counts as "trusted."
PS: Yeah, I hate FB too. It's the only way I have to communicate with some folks. Believe me, given the option, I'd make em all use Signal or XMPP.
My grandpa won't install Signal because he doesn't want another messaging app. I know he uses SMS and WhatsApp at minimum
Last time I removed malware from my grandma's smartphone, I made sure to install Signal to it. Sometimes you just got to demonstrate to them how low impact a change is. Many elderly are frightened by the idea that their experience changes, on a device they depend on but hardly understand. So demonstrate, rather than trying to convince them of something they fail to understand. The worst that can happen is that they tell you to remove it again, but in case of my grandma, she comfortably uses Signal. Just make sure you send some example messages back and forth, so they understand how similar the workflow is.