Pet peeve d'jour:
My 76YO mother in law has a Samsung tablet. It got cluttered enough that she wanted us to factory reset it, which we did. Now, it recognizes that it has been factory reset and wants the GMail account and password that was originally used to initialize it when new.
No problem, she's 76YO, she's only ever had one GMail account and 76YO's don't like changing passwords so it's the original password. Provably correct, we can log into GMail, create messages, etc. Yet the tablet refuses it with an "Unknown error, please try again in 24 hours" message.
No problem, we'll use the telephone backup scheme. Enter in the phone number originally used to initialize the tablet. Text message arrives. We enter the code, tablet seems happy... and then it demands the GMail authentication data again. And refuses it again.
We wait 24 hours.
We wait 48 hours.
We wait a week.
We wait a MONTH.
No improvement. Nothing changes. We reach out to Google and they say their database is fine, and how can we argue? The login credentials work perfectly.
We reach out to Samsung and after 90+ minutes of waiting, I have another appointment and have to disconnect.
I'm now in a chat with Samsung that's lasted an hour so far. I'm being elevated to the third level from whomever originally answered. Nobody even attempts a solution, they just keep elevating the session.
It is a fundamental design error to brick a device due to a loss of sync with a remote database. This tablet is 100% functionally perfect, yet it is 100% functionally useless because Samsung and Google cannot validate an email account. I understand the desire to discourage theft, but the telephone backup should be sufficient to obviate all other authentication steps and give you a true factory reset. Except it's not. And so here's my 76YO mother-in-law's tablet, in perfect condition, and completely worthless.
This "feature" is filling landfills with tablets.