I have 2 zoho accounts, both have been persistently signed into and never signed out of on my Samsung Email app on Android 13.

Out of nowhere, without making any configuration whatsoever, one of those emails stopped working. Keeps asking for some kind of verification. I removed it and re-added it, but I cannot sign back in at all with IMAP.

It keeps saying to sign in with Web Browser to verify your identity. I did this. This was a lie, the browser asks for no verification and even after signing in, I have the same issue.

I can log in with manual set up to POP - however I find this feature totally useless and want to go back to IMAP on my mobile.

I have checked all security settings and mail settings. Nothing at all out of the ordinary and everything as it it should be.
I checked mail settings, toggled IMAP and POP on/off. Nothing happens, matter of fact if I disable IMAP completely the error messages do not change.

As I said I have 2 accounts, one is still working, I have checked all settings side by side and there is no difference.
Obviously I tried changing the password. I created an app specific password under my Account > Security. You can guess the rest. I have tried disabling/enabling Adguard and VPN across my devices.

I have ruled out there being any problem with any aspect except the account itself.
> It is not a 3rd party app issue, I have tried several apps on Android and Windows all give the same results.
> It is not a Zoho issue in general, I have 2 accounts and only 1 is affected

> There are no security issues, I can log in via web browser, but this service is unbearable on mobile and I have no instant push notifications
> I can log in with POP, but never IMAP

For no reason whatsoever, my account of 10 years has become useless overnight. After 10 years I have a lot of sign ins using this account, now begins the process of creating a new account (never again with zoho) and having to change my credentials so many times.