Laptop gets emails but why not my cellphone anymore?

So I have a Macbook and I logged in with my email as normal, but for a long time now I've only received messages on my laptop and when I open "Email" on my mobile phone, no emails are displayed.

How can I get emails on both devices?

Then the emails are downloaded to the MB and deleted from the mailbox.

But you're already logged into your mail accounts on your mobile phone, aren't you?

Yes, I still got emails a few months ago