Can't retrieve new email on one device

Can't retrieve new email on one device

On my phone, one of the email accounts suddenly stopped retrieving new emails. (The email account is being retrieved from a server other than zoho.com.) No matter what I do, I can't seem to get this device to retrieve new emails for this account, although the other accounts still work normally.

But then if I go to my desktop, new emails for this account are retrieved as expected.

I don't even know how this is possible. Please help.