emails folders with no email in them

My emails work fine on my iphone but my wife who shares my account has issues with her emails.

Here email is [mod: PII redacted]@bellsouth.net.. On the desk top computer everthing works great but on he I-phone 6 pro there is an issue.. Can get an email and read it and save to a folder but when you go back to look at it, it's gone.. None of her email folders on her phone have any of the emails in them.

My emails work fine with same I-phone and same email account.. I added her email to my phone and still have the same problem. Thinking there could be security setting in my Microsoft account that's blocking her emails to be sent to her i-phone.