Hotmail disappearance

[TheHillIsMine]

I use the Gmail app to see my gmail and Hotmail emails. All come through the one app and I can see them all. If I go into outlook I'd have to click on the icon separately. Outlook has sorted it so I can see both addresses on there but I hate the app and want my hotmail emails back in gmail. I've done everything it asks and nothing is working. Please can someone help? This is the third time they've just vanished and it's been working fine for years.

In Gmail at the top where your initial is, add another account, choose Hotmail.
then when you view inboxes in the left hand side (where it says drafts etc) choose All Inboxes?

I can do add account, click on hotmail, put in my email address, it asks for the last four digits of my phone to verify then it says can't verify that way at the moment.

All inboxes is also missing. It says it on my phone, not iPad, but it is only showing the gmail emails.